the amount of light reflected from the front surface of common window glass is about

Such coatings can reduce the reflection for ordinary glass from about 4% per surface to around 2%. These were the first type of antireflection coating known, having been discovered by Lord Rayleigh in 1886. He found that old, slightly tarnished pieces of glass transmitted more light than new, clean pieces due to this effect.

Optical coating

An optical coating is one or more thin layers of material deposited on an optical component such as a lens or mirror, which alters the way in which the optic reflects and transmits light. One type of optical coating is an antireflection coating, which reduces unwanted reflections from surfaces, and is commonly used on spectacle and photographic lenses. Another type is the high-reflector coating which can be used to produce mirrors which reflect greater than 99.99% of the light which falls on them. More complex optical coatings exhibit high reflection over some range of wavelengths, and anti-reflection over another range, allowing the production of dichroic thin-film optical filters.

The simplest optical coatings are thin layers of metals, such as aluminium, which are deposited on glass substrates to make mirror surfaces, a process known as silvering. The metal used determines the reflection characteristics of the mirror; aluminium is the cheapest and most common coating, and yields a reflectivity of around 88%-92% over the visible spectrum. More expensive is silver, which has a reflectivity of 95%-99% even into the far infrared, but suffers from decreasing reflectivity (<90%) in the blue and ultraviolet spectral regions. Most expensive is gold, which gives excellent (98%-99%) reflectivity throughout the infrared, but limited reflectivity at wavelengths shorter than 550 nm, resulting in the typical gold colour.

By controlling the thickness and density of metal coatings, it is possible to decrease the reflectivity and increase the transmission of the surface, resulting in a half-silvered mirror. These are sometimes used as "one-way mirrors".

The other major type of optical coating is the dielectric coating (i.e. using materials with a different refractive index to the substrate). These are constructed from thin layers of materials such as magnesium fluoride, calcium fluoride, and various metal oxides, which are deposited onto the optical substrate. By careful choice of the exact composition, thickness, and number of these layers, it is possible to tailor the reflectivity and transmitivity of the coating to produce almost any desired characteristic. Reflection coefficients of surfaces can be reduced to less than 0.2%, producing an antireflection (AR) coating. Conversely, the reflectivity can be increased to greater than 99.99%, producing a high-reflector (HR) coating. The level of reflectivity can also be tuned to any particular value, for instance to produce a mirror that reflects 90% and transmits 10% of the light that falls on it, over some range of wavelengths. Such mirrors are often used as beamsplitters, and as output couplers in lasers. Alternatively, the coating can be designed such that the mirror reflects light only in a narrow band of wavelengths, producing an optical filter.

The versatility of dielectric coatings leads to their use in many scientific optical instruments (such as lasers, optical microscopes, refracting telescopes, and interferometers) as well as consumer devices such as binoculars, spectacles, and photographic lenses.

Dielectric layers are sometimes applied over top of metal films, either to provide a protective layer (as in silicon dioxide over aluminium), or to enhance the reflectivity of the metal film. Metal and dielectric combinations are also used to make advanced coatings that cannot be made any other way. One example is the so-called "perfect mirror", which exhibits high (but not perfect) reflection, with unusually low sensitivity to wavelength, angle, and polarization.[1]

Antireflection coatings are used to reduce reflection from surfaces. Whenever a ray of light moves from one medium to another (such as when light enters a sheet of glass after travelling through air), some portion of the light is reflected from the surface (known as the interface) between the two media.

A number of different effects are used to reduce reflection. The simplest is to use a thin layer of material at the interface, with an index of refraction between those of the two media. The reflection is minimized when

where

n

1

{\displaystyle n_{1}}

 is the index of the thin layer, and

n

0

{\displaystyle n_{0}}

 and

n

S

{\displaystyle n_{S}}

 are the indices of the two media. The optimum refractive indices for multiple coating layers at angles of incidence other than 0Â° is given by Moreno et al. (2005).[2]

Practical antireflection coatings rely on an intermediate layer not only for its direct reduction of reflection coefficient, but also use the interference effect of a thin layer. If the layer's thickness is controlled precisely such that it is exactly one-quarter of the wavelength of the light (a quarter-wave coating), the reflections from the front and back sides of the thin layer will destructively interfere and cancel each other.

In practice, the performance of a simple one-layer interference coating is limited by the fact that the reflections only exactly cancel for one wavelength of light at one angle, and by difficulties finding suitable materials. For ordinary glass (n≈1.5), the optimum coating index is n≈1.23. Few useful substances have the required refractive index. Magnesium fluoride (MgF2) is often used, since it is hard-wearing and can be easily applied to substrates using physical vapour deposition, even though its index is higher than desirable (n=1.38). With such coatings, reflection as low as 1% can be achieved on common glass, and better results can be obtained on higher index media.

Further reduction is possible by using multiple coating layers, designed such that reflections from the surfaces undergo maximum destructive interference. By using two or more layers, broadband antireflection coatings which cover the visible range (400-700Â nm) with maximum reflectivities of less than 0.5% are commonly achievable. Reflection in narrower wavelength bands can be as low as 0.1%. Alternatively, a series of layers with small differences in refractive index can be used to create a broadband antireflective coating by means of a refractive index gradient.

High-reflection (HR) coatings work the opposite way to antireflection coatings. The general idea is usually based on the periodic layer system composed from two materials, one with a high index, such as zinc sulfide (n=2.32) or titanium dioxide (n=2.4) and low index material, such as magnesium fluoride (n=1.38) or silicon dioxide (n=1.49). This periodic system significantly enhances the reflectivity of the surface in the certain wavelength range called band-stop, whose width is determined by the ratio of the two used indices only (for quarter-wave system), while the maximum reflectivity is increasing nearly up to 100% with a number of layers in the stack. The thicknesses of the layers are generally quarter-wave (then they yield to the broadest high reflection band in compare to the non-quarter-wave systems composed from the same materials), this time designed such that reflected beams constructively interfere with one another to maximize reflection and minimize transmission. The best of these coatings built-up from deposited dielectric lossless materials on the perfect smooth surfaces can reach reflectivities greater than 99.999% (over a fairly narrow range of wavelengths). Common HR coatings can achieve 99.9% reflectivity over a broad wavelength range (tens of nanometers in the visible spectrum range).

As for AR coatings, HR coatings are affected by the incidence angle of the light. When used away from normal incidence, the reflective range shifts to shorter wavelengths, and becomes polarization dependent. This effect can be exploited to produce coatings that polarize a light beam.

By manipulating the exact thickness and composition of the layers in the reflective stack, the reflection characteristics can be tuned to a particular application, and may incorporate both high-reflective and anti-reflective wavelength regions. The coating can be designed as a long- or short-pass filter, a bandpass or notch filter, or a mirror with a specific reflectivity (useful in lasers). For example, the dichroic prism assembly used in some cameras requires two dielectric coatings, one long-wavelength pass filter reflecting light below 500 nm (to separate the blue component of the light), and one short-pass filter to reflect red light, above 600 nm wavelength. The remaining transmitted light is the green component.

In the EUV portion of the spectrum (wavelengths shorter than about 30Â nm) nearly all materials absorb strongly, making it difficult to focus or otherwise manipulate light in this wavelength range. Telescopes such as TRACE or EIT that form images with EUV light use multilayer mirrors that are constructed of hundreds of alternating layers of a high-mass metal such as molybdenum or tungsten, and a low-mass spacer such as silicon, vacuum deposited onto a substrate such as glass. Each layer pair is designed to have a thickness equal to half the wavelength of light to be reflected. Constructive interference between scattered light from each layer causes the mirror to reflect EUV light of the desired wavelength as would a normal metal mirror in visible light. Using multilayer optics it is possible to reflect up to 70% of incident EUV light (at a particular wavelength chosen when the mirror is constructed).

Transparent conductive coatings are used in applications where it is important that the coating conduct electricity or dissipate static charge. Conductive coatings are used to protect the aperture from electromagnetic Interference, while dissipative coatings are used to prevent the build-up of static electricity. Transparent conductive coatings are also used extensively to provide electrodes in situations where light is required to pass, for example in flat panel display technologies and in many photoelectrochemical experiments. A common substance used in transparent conductive coatings is indium tin oxide (ITO). ITO is not very optically transparent, however. The layers must be thin to provide substantial transparency, particularly at the blue end of the spectrum. Using ITO, sheet resistances of 20 to 10,000 ohms per square can be achieved. An ITO coating may be combined with an antireflective coating to further improve transmittance. Other TCOs (Transparent Conductive Oxides) include AZO (Aluminium doped Zinc Oxide), which offers much better UV transmission than ITO. A special class of transparent conductive coatings applies to infrared films for theater-air military optics where IR transparent windows need to have (Radar) stealth (Stealth technology) properties. These are known as RAITs (Radar Attenuating / Infrared Transmitting) and include materials such as boron doped DLC (Diamond-like carbon)[citation needed].

Estimated at US$6.5 billion in 2013, the global demand of optical coatings is forecast to grow 6.5% annually over the next years. The largest application market of optical coatings is electronics and semiconductor combined, while the fastest growing one is fiber optics & telecommunication combined.[3]


who does michiel huisman play on game of thrones

Michiel Huisman (Dutch pronunciation: [miˈɣil ˈɦœysmɑn]; born 18 July 1981) is a Dutch actor, musician, and singer-songwriter, who has acted in both Dutch and English language TV series and films. Huisman played Ellis Jones in the fantasy romance film The Age of Adaline (2015), Sonny on the television series Treme (2010–2013), and Daario Naharis on Game of Thrones (2014–2016). He has also played recurring roles on television such as Liam McGuinnis on Nashville (2012–2014) and as Cal Morrison on Orphan Black (2014–2015).

Michiel Huisman

Huisman began his career on Dutch television, in the Dutch soap opera Goede tijden, slechte tijden (1998). He later played starring roles in the Dutch TV series De co-assistent (2007â€“2010) and Bloedverwanten (2010), supporting roles in the Dutch films Costa! (2001) and Full Moon Party (2002), and leading roles in Phileine Says Sorry (2003) and Floris (2004). He also played a supporting role in Black Book (2006). During the early years of his acting career, Huisman was also part of a band called Fontane.

Huisman's first international acting experience came in 2006, when he guest-starred in an episode of the British TV series Dalziel and Pascoe. He subsequently appeared in The Young Victoria (2009), World War Z (2013), Wild (2014), The Invitation (2015) and The Age of Adaline (2015).

Michiel Huisman was born on 18 July 1981 in Amstelveen, a town near Amsterdam, in the Netherlands.

Huisman is married to Dutch actress Tara Elders.[1] They have a daughter born in 2007.[2] The couple used to live in New Orleans, Louisiana, [1] but as of 2017 they have taken up residence in New York City in a McIntyre Building.[citation needed]

Huisman was singer and guitarist in the Dutch band Fontane, which he formed together with Roland van der Hoofd, Gilles Tuinder, Bas van Geldere, and Donny Griffioen.[3] The band released the singles "1+1=2" (2001), "Slapeloos" (2002), and "Neem Me Mee" (2003).[4] The first single was on the soundtrack of the film Costa! (2001) and the second was on the soundtrack of Full Moon Party (2002), both in which Huisman played a starring role. The band also recorded a version of Willeke Alberti's song "Telkens weer" for the soundtrack of the movie Love to Love (2003).[5]

After two members left the band, Fontane split up and Huisman decided to pursue music on his own.[5] Huisman released the singles "Deel Van Mij" (2005) and "Geef Je Over" (2006), and the album Luchtige Verhalen (2005) as a solo artist.[6] Huisman said in interview about his solo career: "It doesn't feel like a new start, but as if I've started just now." and "It is personal and closerby. Also the sound of the album."[5]

Huisman began his acting career with a supporting role on Goede Tijden, Slechte Tijden – the longest-running soap opera on Dutch television – where he played Rover, a 14-year-old model who accuses his employers of engaging in child pornography. He was then cast in the made-for-TV films Suzy Q and Uitgesloten.

He played supporting roles in the Dutch films Costa! and Volle Maan, both of which were directed by Johan Nijenhuis and aimed at a teen-aged audience. At the same time, he also had a recurring role on the Dutch police series Spangen. Huisman moved into leading-man territory in 2003 with the film Phileine Says Sorry, which was an adaptation of Ronald Giphart's book of the same title. He also starred as medieval knight Floris in the film Floris, based on the Dutch TV series.

In the years that followed he played a leading role in the football comedy Johan, recurring guest roles in the comedy series Meiden van De Wit and the first season of the drama series Bloedverwanten, and the leading role in the medical drama series De Co-Assistent. He also played a small supporting role in the 2006 film Zwartboek by Paul Verhoeven, which became the most successful Dutch film of all time.[7]

In 2006, Huisman made his first foray into the international acting world with a supporting role in an episode of the British TV series Dalziel and Pascoe. He followed this with a role as Ernest II, Duke of Saxe-Coburg and Gotha in The Young Victoria, and the BBC made-for-TV drama Margot in which he portrayed Rudolf Nureyev. He then joined the main cast of the HBO series Treme, as Sonny, a Dutch busker who plays keyboards and guitar. He was taught New Orleans piano by Davis Rogan.[8] During his time on Treme, Huisman also played a small supporting role in the apocalyptic action film World War Z and started recurring as Liam McGuinnis on Nashville.

Huisman replaced British actor Ed Skrein in the role of Daario Naharis for the fourth season (2014) of Game of Thrones.[9] Huisman was promoted to series regular for the fifth season (2015) of the series.[10] Huisman also recurred on seasons 2 and 3 of Orphan Black, portraying Cal Morrison, a rugged outdoorsman who crosses paths with the clones.[11]

In 2014, Huisman appeared in the Academy Award-nominated biographical drama film Wild[12] and starred in the advertising campaign for Chanel No.5's The One That I Want, which was directed by Baz Luhrmann.[13] In 2015, Huisman appeared in the thriller The Invitation,[14] and played the leading role in the 2015 fantasy romance film The Age of Adaline.

In 2016, Huisman was cast as the lead role in the war-drama The Ottoman Lieutenant which tells the story of a Turkish officer (Huisman) who falls in love with an idealistic American nurse during World War I. The film also stars Hera Hilmar as Huisman's love interest, as well as Josh Hartnett and Ben Kingsley. The film was released for an Oscar-qualifying run in December 2016 before releasing wide in March 2017.[15][16]

Also in 2016, Huisman played Walter Davidson in a Discovery Channel limited series titled Harley and the Davidsons which told the origin story of Harley-Davidson Inc.[17] The three-part series premiered in September 2016, and gained reasonable[specify] reviews from critics[18] and from Harley-Davidson themselves.[19]

In November 2016, Huisman was cast opposite Lily James to star as the male lead in the romantic drama Guernsey, based on the 2008 novel The Guernsey Literary and Potato Peel Pie Society.[20] In 2017 Huisman was announced to play the male lead in another romantic drama titled Irreplaceable You, which will tell the story of Abbie and Sam, soul mates who were destined to be together until death got in the way.[21] The film will also star Gugu Mbatha-Raw, Steve Coogan and Christopher Walken.[22]

Huisman was signed to star in the thriller film 2:22 which is set to be released June 30, 2017.[23][24] Also in June 2017, Huisman was cast to star in the upcoming Netflix TV-series The Haunting of Hill House, which is based on the Shirley Jackson classic 1959 novel of the same name. The straight-to-series 10-episode drama is described as a modern reimagining of the tale, and will follow four people living in an 80-year-old mansion. Huisman is set to play Steven Crane, the oldest Crane sibling and a published writer of supernatural books — including a memoir about his family’s time living at Hill House. Filmaker Mike Flanagan will write, direct and executive produce the series.[25]

Singles with Fontane


who had the first interracial kiss on tv

In June 1962, a live performance of the play You in Your Small Corner by Barry Reckord was broadcast on British television as part of the series Granada Play of the Week. The central theme of the play is a relationship between a young black intellectual and a white working class girl. During the play, a kiss takes place between actors Lloyd Reckord and Elizabeth MacLennan, and what has been described as an "explicit post-coital scene".[1]

First interracial kiss on television

The first interracial kiss on television is a much debated topic concerning who the first two persons of different races to kiss on television were. For a time, it was understood to have occurred during an episode of the British soap opera Emergency – Ward 10 in 1964. However, in November 2015, a Granada Play of the Week, You in Your Small Corner, was uncovered which was broadcast in June 1962; that quickly led to the rediscovery of another play featuring the same young Jamaican actor, Hot Summer Night, televised in Britain on 1 February 1959. The first interracial kiss on U.S. television was broadcast in a 1960 episode of Adventures in Paradise, "Makaha Surfing", also known as "The Big Surf", between star Gardner McKay and Filipina Pilar Seurat. Competing claims have also been made in favour of I Love Lucy.

You In Your Small Corner was rediscovered during preparations for a November 2015 British Film Institute panel discussion on "Race and Romance on TV" and was used in publicity for the event. As a result, panel moderator Samira Ahmed was able, on the night, to announce the rediscovery of an even earlier TV kiss by Lloyd Reckord, with Andrée Melly, in the ITV Armchair Theatre adaptation of Ted Willis's play Hot Summer Night, broadcast on 1 February 1959.[2][3]

One of the earliest interracial kisses on television occurred in a July 1964 episode of British soap opera Emergency Ward 10, during which characters Louise Mahler (portrayed by Joan Hooley) and Giles Farmer (portrayed by John White) kissed.[1][4][5] The scene in which Mahler and Farmer kissed was originally scripted to occur in Mahler's bedroom, but was rewritten so as to occur outdoors, due to concerns it would otherwise be too risquÃ© (the earlier Lloyd Reckord plays had both been shown well after the 9pm adult-content watershed). According to an issue of the Daily Express published after the episode aired, "not a viewer rang-up to complain".[6] In a 2015 interview, conducted prior to the discovery of the You in Your Small Corner footage, Hooley noted that the historic importance of what had been known as the "first interracial kiss on television" had been inflated in popular memory:

A lot of people spoke about it more ten years later than they did at the time it was happening. So, it was much later that it occurred to me that I was part of history. I find it odd to have to admit that I was part of history because I don't see why there should be anything to do about it. I don't think there should have been all this fuss about it.

The 1950s American television programme I Love Lucy broadcast multiple instances of real-life husband and wife Desi Arnaz, a Hispanic male, and Lucille Ball, a woman of North European ancestry, kissing.[7] However, despite Arnaz and Ball being frequently described as an "interracial couple", "Hispanic" is generally understood to be a catchall indicating persons of a Latin American, Iberian, or Filipino cultural background, as opposed to a race. Arnaz was usually considered to be a white male of Cuban ancestry.[8]

A January 5, 1966 episode of I Spy titled "The Tiger"[9] featured a scripted interracial kiss between Eurasian actress France Nuyen and Robert Culp almost two years before "Plato's Stepchildren".[10]

A December 1967 episode of Movin' with Nancy featured a kiss between Nancy Sinatra and Sammy Davis, Jr., more than a year before the Star Trek episode "Plato's Stepchildren" aired.[11]

A 1968 episode of Star Trek, "Plato's Stepchildren",[1][12] which first aired on November 22, 1968, is often referred to as the first interracial kiss on American television. This claim is disputed by some who contend that in the scene in question, full lip contact between William Shatner and Nichelle Nichols did not occur, as the actors turned their heads away from the camera at the last moment to present the illusion of a kiss, meaning that this scene was not a true kiss.[13] The latter point has been disputed, with Shatner claiming that he and Nichols' lips never fully touched and Nichols asserting that the kiss was real.[14]

It is often ignored that "Mirror, Mirror", which originally aired on October 6, 1967, featured a scripted interracial kiss between Eurasian actress Barbara Luna and the aforementioned William Shatner a year prior.[15]


who is the founder of byju's app

BYJUâ€™S - The Learning App is the popular brand name for Think and Learn Private Ltd., a Alipur-based Educational technology (edtech) and online tutoring firm.
It was founded in 2011 by Byju Raveendran at

BYJU’s

In fact, Byju himself comes from a small village in Kerala, Azhikode.
BYJU'S was the first investment in Asia from the Chan Zuckerberg Initiative.[1] It is considered to be one among the only few Indian consumer startups that has gone global,[2] particularly with the 2017 acquisition of TutorVista.

Their flagship product is a smartphone app named BYJU'S-The Learning App that has been available since August 2015.[3]
The App serves educational content mainly to school students from classes 4 to 12 (primary to higher secondary level education).
The company trains students for competitive examinations in India such as IIT-JEE, NEET, CAT, IAS as well as for international examinations such as GRE and GMAT.

The main focus is on mathematics and science, where the concepts are visually explained and in context [4]
using modern digital animations
[5]
and moving illustrations, all embedded within short videos (15-20 minutes long).[6] The app has received criticism for a few issues such as lack of depth in some areas, overly simplistic treatment of some basic topics, and lack of within-lecture student-teacher interaction.
In spite of the adverse critical opinion and competition from other players (including Edtech startups and traditional education firms), the app has enjoyed tremendous popularity. BYJU'S reports to have over 15 million users overall and about nine lakh paid subscribers on an annual basis [7] and an annual retention rate of about 90%.[2]

BYJU'S operates roughly on a freemium business model where a paid subscription is required for most of the content.[4]

As of April 2018, the company has raised around $244 million.[7] The major investors and stakeholders include Chan Zuckerberg Initiative (CZI), Sequoia Capital, Sofina, Lightspeed Venture Partners, Verlinvest, Aarin Capital and Times Internet (Times of India group).[7]
This was the first investment from CZI (co-funded by Facebook founder Mark Zuckerberg and Priscilla Chan) in Asia.[1][8][9]

As per the company filings with the Ministry of Corporate Affairs, BYJUâ€™S became a unicorn and is valued at US$1 billion (INR 6,505 Crore) in March 2018. [10]

In FY 2016-17, BYJUâ€™S saw its revenue more than double and its losses increase by 10% as compared to the last financial year 2015-16. Gross revenue for FY 2016-17 jumped to $36 Mn (INR 247 Crore) from $16 Mn (INR 110 Crore) in the previous year, clocking a 124% Year-on-Year growth. On the expense front, BYJU'S total expenses grew by 87% from $23 Mn (INR 156 Crore) to $43 Mn (INR 291 Crore), while in FY15-16 this increment was 104%.[11]

In June 2017, BYJU'S acquired the online education businesses of TutorVista and Edurite from Pearson, the world's leading educational and publishing company.[12]


the main storage site for fat in the body is

Ectopic fat is the storage of triglycerides in tissues other than adipose tissue, that are supposed to contain only small amounts of fat, such as the liver, skeletal muscle, heart, and pancreas.[1] This can interfere with cellular functions and hence organ function and is associated with insulin resistance in type-2 diabetes.[37] It is stored in relatively high amounts around the organs of the abdominal cavity, but is not to be confused as visceral fat.

Adipose tissue

In biology, adipose tissue /ˈædɪˌpoʊs/ ( listen), body fat, or simply fat is a loose connective tissue composed mostly of adipocytes.[1] In addition to adipocytes, adipose tissue contains the stromal vascular fraction (SVF) of cells including preadipocytes, fibroblasts, vascular endothelial cells and a variety of immune cells such as adipose tissue macrophages. Adipose tissue is derived from preadipocytes. Its main role is to store energy in the form of lipids, although it also cushions and insulates the body. Far from being hormonally inert, adipose tissue has, in recent years, been recognized as a major endocrine organ,[2] as it produces hormones such as leptin, estrogen, resistin, and the cytokine TNFα. The two types of adipose tissue are white adipose tissue (WAT), which stores energy, and brown adipose tissue (BAT), which generates body heat. The formation of adipose tissue appears to be controlled in part by the adipose gene. Adipose tissue – more specifically brown adipose tissue – was first identified by the Swiss naturalist Conrad Gessner in 1551.[3]

In humans, adipose tissue is located beneath the skin (subcutaneous fat), around internal organs (visceral fat), in bone marrow (yellow bone marrow), intermuscular (Muscular system) and in the breast tissue. Adipose tissue is found in specific locations, which are referred to as adipose depots. Apart from adipocytes, which comprise the highest percentage of cells within adipose tissue, other cell types are present, collectively termed stromal vascular fraction (SVF) of cells. SVF includes preadipocytes, fibroblasts, adipose tissue macrophages, and endothelial cells. Adipose tissue contains many small blood vessels. In the integumentary system, which includes the skin, it accumulates in the deepest level, the subcutaneous layer, providing insulation from heat and cold. Around organs, it provides protective padding. However, its main function is to be a reserve of lipids, which can be oxidised to meet the energy needs of the body and to protect it from excess glucose by storing triglycerides produced by the liver from sugars, although some evidence suggests that most lipid synthesis from carbohydrates occurs in the adipose tissue itself.[4] Adipose depots in different parts of the body have different biochemical profiles. Under normal conditions, it provides feedback for hunger and diet to the brain.

Mice have eight major adipose depots, four of which are within the abdominal cavity.[1] The paired gonadal depots are attached to the uterus and ovaries in females and the epididymis and testes in males; the paired retroperitoneal depots are found along the dorsal wall of the abdomen, surrounding the kidney, and, when massive, extend into the pelvis. The mesenteric depot forms a glue-like web that supports the intestines and the omental depot (which originates near the stomach and spleen) and - when massive - extends into the ventral abdomen. Both the mesenteric and omental depots incorporate much lymphoid tissue as lymph nodes and milky spots, respectively. The two superficial depots are the paired inguinal depots, which are found anterior to the upper segment of the hind limbs (underneath the skin) and the subscapular depots, paired medial mixtures of brown adipose tissue adjacent to regions of white adipose tissue, which are found under the skin between the dorsal crests of the scapulae. The layer of brown adipose tissue in this depot is often covered by a "frosting" of white adipose tissue; sometimes these two types of fat (brown and white) are hard to distinguish. The inguinal depots enclose the inguinal group of lymph nodes. Minor depots include the pericardial, which surrounds the heart, and the paired popliteal depots, between the major muscles behind the knees, each containing one large lymph node.[5] Of all the depots in the mouse, the gonadal depots are the largest and the most easily dissected,[6] comprising about 30% of dissectible fat.[7]

In an obese person, excess adipose tissue hanging downward from the abdomen is referred to as a panniculus. A panniculus complicates surgery of the morbidly obese individual. It may remain as a literal "apron of skin" if a severely obese person quickly loses large amounts of fat (a common result of gastric bypass surgery). This condition cannot be effectively corrected through diet and exercise alone, as the panniculus consists of adipocytes and other supporting cell types shrunken to their minimum volume and diameter.[citation needed] Reconstructive surgery is one method of treatment.[citation needed]

Visceral fat or abdominal fat[8] (also known as organ fat or intra-abdominal fat) is located inside the abdominal cavity, packed between the organs (stomach, liver, intestines, kidneys, etc.). Visceral fat is different from subcutaneous fat underneath the skin, and intramuscular fat interspersed in skeletal muscles. Fat in the lower body, as in thighs and buttocks, is subcutaneous and is not consistently spaced tissue, whereas fat in the abdomen is mostly visceral and semi-fluid.[9] Visceral fat is composed of several adipose depots, including mesenteric, epididymal white adipose tissue (EWAT), and perirenal depots. Visceral fat is often expressed in terms of its area in cm2 (VFA, visceral fat area).[10]

An excess of visceral fat is known as central obesity, or "belly fat", in which the abdomen protrudes excessively. New developments such as the Body Volume Index (BVI) are specifically designed to measure abdominal volume and abdominal fat. Excess visceral fat is also linked to type 2 diabetes,[11] insulin resistance,[12] inflammatory diseases,[13] and other obesity-related diseases.[14] Likewise, the accumulation of neck fat (or cervical adipose tissue) has been shown to be associated with mortality.[15] Several studies have suggested that visceral fat can be predicted from simple anthropometic measures,[16] and predicts mortality more accurately than body mass index or waist circumference.[17]

Men are more likely to have fat stored in the abdomen due to sex hormone differences. Female sex hormone causes fat to be stored in the buttocks, thighs, and hips in women.[18][19] When women reach menopause and the estrogen produced by the ovaries declines, fat migrates from the buttocks, hips and thighs to the waist;[20] later fat is stored in the abdomen.[21]

High-intensity exercise is one way to effectively reduce total abdominal fat.[22][23] One study suggests at least 10 MET-hours per week of aerobic exercise is required for visceral fat reduction.[24]

Epicardial adipose tissue (EAT) is a particular form of visceral fat deposited around the heart and found to be a metabolically active organ that generates various bioactive molecules, which might significantly affect cardiac function.[25] Marked component differences have been observed in comparing EAT with subcutaneous fat, suggesting a depot specific impact of stored fatty acids on adipocyte function and metabolism.[26]

Most of the remaining nonvisceral fat is found just below the skin in a region called the hypodermis.[27] This subcutaneous fat is not related to many of the classic obesity-related pathologies, such as heart disease, cancer, and stroke, and some evidence even suggests it might be protective.[28] The typically female (or gynecoid) pattern of body fat distribution around the hips, thighs, and buttocks is subcutaneous fat, and therefore poses less of a health risk compared to visceral fat.[29]

Like all other fat organs, subcutaneous fat is an active part of the endocrine system, secreting the hormones leptin and resistin.[27]

The relationship between the subcutaneous adipose layer and total body fat in a person is often modelled by using regression equations. The most popular of these equations was formed by Durnin and Wormersley, who rigorously tested many types of skinfold, and, as a result, created two formulae to calculate the body density of both men and women. These equations present an inverse correlation between skinfolds and body densityâ€”as the sum of skinfolds increases, the body density decreases.[30]

Factors such as sex, age, population size or other variables may make the equations invalid and unusable, and, as of 2012[update], Durnin and Wormersley's equations remain only estimates of a person's true level of fatness. New formulae are still being created.[30]

Marrow fat, also known as marrow adipose tissue (MAT), is a poorly understood adipose depot that resides in the bone and is interspersed with hematopoietic cells as well as bony elements. The adipocytes in this depot are derived from mesenchymal stem cells (MSC) which can give rise to fat cells, bone cells as well as other cell types. The fact that MAT increases in the setting of calorie restriction/ anorexia is a feature that distinguishes this depot from other fat depots.[31][32][33] Exercise regulates MAT, decreasing MAT quantity and diminishing the size of marrow adipocytes.[34][35][36] The exercise regulation of marrow fat suggests that it bears some physiologic similarity to other white adipose depots. Moreover, increased MAT in obesity further suggests a similarity to white fat depots.[34]

The specific cause for the accumulation of ectopic fat is unknown. The cause is likely a combination of genetic, environmental, and behavioral factors that are involved in excess energy intake and decreased physical activity. Substantial weight loss can reduce ectopic fat stores in all organs and this is associated with an improvement of the function of that organ.[37]

In the latter case, non-invasive weight loss interventions like diet or exercise have the ability to decrease ectopic fat (particularly in heart and liver) in children and adults with overweight or obesity.[38][39]

Free fatty acids are liberated from lipoproteins by lipoprotein lipase (LPL) and enter the adipocyte, where they are reassembled into triglycerides by esterifying it onto glycerol. Human fat tissue contains about 87% lipids[citation needed].

There is a constant flux of FFA (Free Fatty Acids) entering and leaving adipose tissue. The net direction of this flux is controlled by insulin and leptinâ€”if insulin is elevated, then there is a net inward flux of FFA, and only when insulin is low can FFA leave adipose tissue. Insulin secretion is stimulated by high blood sugar, which results from consuming carbohydrates.[citation needed]

In humans, lipolysis (hydrolysis of triglycerides into free fatty acids) is controlled through the balanced control of lipolytic B-adrenergic receptors and a2A-adrenergic receptor-mediated antilipolysis.

Fat cells have an important physiological role in maintaining triglyceride and free fatty acid levels, as well as determining insulin resistance. Abdominal fat has a different metabolic profileâ€”being more prone to induce insulin resistance. This explains to a large degree why central obesity is a marker of impaired glucose tolerance and is an independent risk factor for cardiovascular disease (even in the absence of diabetes mellitus and hypertension).[40] Studies of female monkeys at Wake Forest University (2009) discovered that individuals suffering from higher stress have higher levels of visceral fat in their bodies. This suggests a possible cause-and-effect link between the two, wherein stress promotes the accumulation of visceral fat, which in turn causes hormonal and metabolic changes that contribute to heart disease and other health problems.[41]

Recent advances in biotechnology have allowed for the harvesting of adult stem cells from adipose tissue, allowing stimulation of tissue regrowth using a patient's own cells. In addition, adipose-derived stem cells from both human and animals reportedly can be efficiently reprogrammed into induced pluripotent stem cells without the need for feeder cells.[42] The use of a patient's own cells reduces the chance of tissue rejection and avoids ethical issues associated with the use of human embryonic stem cells.[43] A growing body of evidence also suggests that different fat depots (i.e. abdominal, omental, pericardial) yield adipose-derived stem cells with different characteristics.[43][44] These depot-dependent features include proliferation rate, immunophenotype, differentiation potential, gene expression, as well as sensitivity to hypoxic culture conditions.[45]

Adipose tissue is the greatest peripheral source of aromatase in both males and females,[citation needed] contributing to the production of estradiol.

Adipose derived hormones include:

Adipose tissues also secrete a type of cytokines (cell-to-cell signalling proteins) called adipokines (adipocytokines), which play a role in obesity-associated complications. Perivascular adipose tissue releases adipokines such as adiponectin that affect the contractile function of the vessels that they surround.[1][46]

Brown fat or brown adipose tissue is a specialized form of adipose tissue in humans and other mammals.[47] It is located mainly around the neck and large blood vessels of the thorax. This specialized tissue can generate heat by "uncoupling" the respiratory chain of oxidative phosphorylation within mitochondria. The process of uncoupling means that when protons transit down the electrochemical gradient across the inner mitochondrial membrane, the energy from this process is released as heat rather than being used to generate ATP. This thermogenic process may be vital in neonates exposed to cold, which then require this thermogenesis to keep warm, as they are unable to shiver, or take other actions to keep themselves warm.[48]

Attempts to simulate this process pharmacologically have so far been unsuccessful. Techniques to manipulate the differentiation of "brown fat" could become a mechanism for weight loss therapy in the future, encouraging the growth of tissue with this specialized metabolism without inducing it in other organs.

Until recently, brown adipose tissue was thought to be primarily limited to infants in humans, but new evidence has now overturned that belief. Metabolically active tissue with temperature responses similar to brown adipose was first reported in the neck and trunk of some human adults in 2007,[49] and the presence of brown adipose in human adults was later verified histologically in the same anatomical regions.[50][51][52]

Browning of WAT, also referred to as “beiging”, occurs when adipocytes within WAT depots develop features of BAT. Beige adipocytes take on a multilocular appearance (containing several lipid droplets) and increase expression of uncoupling protein 1 (UCP1).[53] In doing so, these normally energy-storing adipocytes become energy-releasing adipocytes.

UCP1 is a protein predominantly found in BAT.[54] It acts to dissipate the proton gradient generated by oxidative phosphorylation, leading to the production of heat. Release of catecholamines from sympathetic nerves results in UCP1 activation and usually occurs after extended periods of cold exposure or in response to overfeeding.[55] UCP1 activity is stimulated by long chain fatty acids that are produced subsequent to Î²-adrenergic receptor activation.[56] UCP1 is proposed to function as a fatty acid proton symporter, although the exact mechanism has yet to be elucidated.[57] In contrast, UCP1 is inhibited by ATP, ADP, and GTP.[58]

The calorie-burning capacity of brown and beige fat has been extensively studied as research efforts focus on therapies targeted to treat obesity and diabetes. The drug 2,4-dinitrophenol, which also acts as a chemical uncoupler similarly to UCP1, was used for weight loss in the 1930s. However, it was quickly discontinued when excessive dosing led to adverse side effects including hyperthermia and death.[53] Î²3 agonists, like CL316,243, have also been developed and tested in humans. However, the use of such drugs has proven largely unsuccessful due to several challenges, including varying species receptor specificity and poor oral bioavailability.[59]

Cold is a primary regulator of BAT processes and induces WAT browning. Browning in response to chronic cold exposure has been well documented and is a reversible process. A study in mice demonstrated that cold-induced browning can be completely reversed in 21 days, with measurable decreases in UCP1 seen within a 24-hour period.[60] A study by Rosenwald et al. revealed that when the animals are re-exposed to a cold environment, the same adipocytes will adopt a beige phenotype, suggesting that beige adipocytes are retained.[61]

Transcriptional regulators, as well as a growing number of other factors, regulate the induction of beige fat. Three regulators of transcription are central to WAT browning and serve as targets for many of the molecules known to influence this process.[62] These include peroxisome proliferator-activated receptor gamma (PPARγ), PR domain containing 16 (PRDM16), and peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α).[62] The list of molecules that influence browning has grown in direct proportion to the popularity of this topic and is constantly evolving as more knowledge is acquired. Among these molecules are irisin and fibroblast growth factor 21 (FGF21), which have been well-studied and are believed to be important regulators of browning. Irisin is secreted from muscle in response to exercise and has been shown to increase browning by acting on beige preadipocytes.[63] FGF21, a hormone secreted mainly by the liver, has garnered a great deal of interest after being identified as a potent stimulator of glucose uptake and a browning regulator through its effects on PGC-1α.[53] It is increased in BAT during cold exposure and is thought to aid in resistance to diet-induced obesity[64] FGF21 may also be secreted in response to exercise and a low protein diet, although the latter has not been thoroughly investigated.[65][66] Data from these studies suggest that environmental factors like diet and exercise may be important mediators of browning.

Due to the complex nature of adipose tissue and a growing list of browning regulatory molecules, great potential exists for the use of bioinformatics tools to improve study within this field. Studies of WAT browning have greatly benefited from advances in these techniques, as beige fat is rapidly gaining popularity as a therapeutic target for the treatment of obesity and diabetes.

DNA microarray is a bioinformatics tool used to quantify expression levels of various genes simultaneously, and has been used extensively in the study of adipose tissue. One such study used microarray analysis in conjunction with Ingenuity IPA software to look at changes in WAT and BAT gene expression when mice were exposed to temperatures of 28 and 6 °C.[67] The most significantly up- and downregulated genes were then identified and used for analysis of differentially expressed pathways. It was discovered that many of the pathways upregulated in WAT after cold exposure are also highly expressed in BAT, such as oxidative phosphorylation, fatty acid metabolism, and pyruvate metabolism.[67] This suggests that some of the adipocytes switched to a beige phenotype at 6 °C. Mössenböck et al. also used microarray analysis to demonstrate that insulin deficiency inhibits the differentiation of beige adipocytes but does not disturb their capacity for browning.[68] These two studies demonstrate the potential for the use of microarray in the study of WAT browning.

RNA sequencing (RNA-Seq) is a powerful computational tool that allows for the quantification of RNA expression for all genes within a sample. Incorporating RNA-Seq into browning studies is of great value, as it offers better specificity, sensitivity, and a more comprehensive overview of gene expression than other methods. RNA-Seq has been used in both human and mouse studies in an attempt characterize beige adipocytes according to their gene expression profiles and to identify potential therapeutic molecules that may induce the beige phenotype. One such study used RNA-Seq to compare gene expression profiles of WAT from wild-type (WT) mice and those overexpressing Early B-Cell Factor-2 (EBF2). WAT from the transgenic animals exhibited a brown fat gene program and had decreased WAT specific gene expression compared to the WT mice.[69] Thus, EBF2 has been identified as a potential therapeutic molecule to induce beiging.

Chromatin immunoprecipitation with sequencing (ChIP-seq) is a method used to identify protein binding sites on DNA and assess histone modifications. This tool has enabled examination of epigenetic regulation of browning and helps elucidate the mechanisms by which protein-DNA interactions stimulate the differentiation of beige adipocytes. Studies observing the chromatin landscapes of beige adipocytes have found that adipogenesis of these cells results from the formation of cell specific chromatin landscapes, which regulate the transcriptional program and, ultimately, control differentiation. Using ChIP-seq in conjunction with other tools, recent studies have identified over 30 transcriptional and epigenetic factors that influence beige adipocyte development.[69]

The thrifty gene hypothesis (also called the famine hypothesis) states that in some populations the body would be more efficient at retaining fat in times of plenty, thereby endowing greater resistance to starvation in times of food scarcity. This hypothesis, originally advanced in the context of glucose metabolism and insulin resistance, has been discredited by physical anthropologists, physiologists, and the original proponent of the idea himself with respect to that context, although according to its developer it remains "as viable as when [it was] first advanced" in other contexts.[70][71]

In 1995, Jeffrey Friedman, in his residency at the Rockefeller University, together with Rudolph Leibel, Douglas Coleman et al. discovered the protein leptin that the genetically obese mouse lacked.[72][73][74] Leptin is produced in the white adipose tissue and signals to the hypothalamus. When leptin levels drop, the body interprets this as a loss of energy, and hunger increases. Mice lacking this protein eat until they are four times their normal size.

Leptin, however, plays a different role in diet-induced obesity in rodents and humans. Because adipocytes produce leptin, leptin levels are elevated in the obese. However, hunger remains, and - when leptin levels drop due to weight loss - hunger increases. The drop of leptin is better viewed as a starvation signal than the rise of leptin as a satiety signal.[75] However, elevated leptin in obesity is known as leptin resistance. The changes that occur in the hypothalamus to result in leptin resistance in obesity are currently the focus of obesity research.[76]

Gene defects in the leptin gene (ob) are rare in human obesity.[77] As of July, 2010, only 14 individuals from five families have been identified worldwide who carry a mutated ob gene (one of which was the first ever identified cause of genetic obesity in humans)—two families of Pakistani origin living in the UK, one family living in Turkey, one in Egypt, and one in Austria[78][79][80][81][82]—and two other families have been found that carry a mutated ob receptor.[83][84] Others have been identified as genetically partially deficient in leptin, and, in these individuals, leptin levels on the low end of the normal range can predict obesity.[85]

Several mutations of genes involving the melanocortins (used in brain signaling associated with appetite) and their receptors have also been identified as causing obesity in a larger portion of the population than leptin mutations.[86]

In 2007, researchers isolated the adipose gene, which those researchers hypothesize serves to keep animals lean during times of plenty. In that study, increased adipose gene activity was associated with slimmer animals.[87] Although its discoverers dubbed this gene the adipose gene, it is not a gene responsible for creating adipose tissue.

Pre-adipocytes are undifferentiated fibroblasts that can be stimulated to form adipocytes. Recent studies shed light into potential molecular mechanisms in the fate determination of pre-adipocytes although the exact lineage of adipocyte is still unclear.[88][89]

Adipose tissue has a density of ~0.9 g/ml.[90] Thus, a person with more adipose tissue will float more easily than a person of the same weight with more muscular tissue, since muscular tissue has a density of 1.06 g/ml.[91]

A body fat meter is a widely available tool used to measure the percentage of fat in the human body. Different meters use various methods to determine the body fat to weight ratio. They tend to under-read body fat percentage.[92]

In contrast with clinical tools, one relatively inexpensive type of body fat meter uses the principle of bioelectrical impedance analysis (BIA) in order to determine an individual's body fat percentage. To achieve this, the meter passes a small, harmless, electric current through the body and measures the resistance, then uses information on the person's weight, height, age, and sex to calculate an approximate value for the person's body fat percentage. The calculation measures the total volume of water in the body (lean tissue and muscle contain a higher percentage of water than fat), and estimates the percentage of fat based on this information. The result can fluctuate several percentage points depending on what has been eaten and how much water has been drunk before the analysis.

Within the fat (adipose) tissue of CCR2 deficient mice, there is an increased number of eosinophils, greater alternative Macrophage activation, and a propensity towards type 2 cytokine expression. Furthermore, this effect was exaggerated when the mice became obese from a high fat diet.[93]

Diagrammatic sectional view of the skin (magnified).

White adipose tissue in paraffin section

Electronic instrument of body fat meter


where is mecca located on the world map

Mecca (/ˈmɛkə/; Arabic: مكة[1] Makkah (Hejazi pronunciation: [ˈmakːa,ˈmäkːä]) is a city in the Hejazi region of the Arabian Peninsula, and the plain of Tihamah in Saudi Arabia, and is also the capital and administrative headquarters of the Makkah Region.[8] The city is located 70 km (43 mi) inland from Jeddah in a narrow valley at a height of 277 m (909 ft) above sea level, and 340 kilometres (210 mi) south of Medina. Its resident population in 2012 was roughly 2 million, although visitors more than triple this number every year during the Ḥajj (Arabic: حَـجّ, "Pilgrimage") period held in the twelfth Muslim lunar month of Dhūl-Ḥijjah (Arabic: ذُو الْـحِـجَّـة).

Mecca

As the birthplace of Muhammad, and the site of Muhammad's first revelation of the Quran (specifically, a cave 3 km (2 mi) from Mecca),[9][10] Mecca is regarded as the holiest city in the religion of Islam[11] and a pilgrimage to it known as the Hajj is obligatory for all able Muslims. Mecca is home to the Kaaba, by majority description Islam's holiest site, as well as being the direction of Muslim prayer. Mecca was long ruled by Muhammad's descendants, the sharifs, acting either as independent rulers or as vassals to larger polities. It was conquered by Ibn Saud in 1925. In its modern period, Mecca has seen tremendous expansion in size and infrastructure, home to structures such as the Abraj Al Bait, also known as the Makkah Royal Clock Tower Hotel, the world's fourth tallest building and the building with the third largest amount of floor area. During this expansion, Mecca has lost some historical structures and archaeological sites, such as the Ajyad Fortress.[12] Today, more than 15 million Muslims visit Mecca annually, including several million during the few days of the Hajj.[13] As a result, Mecca has become one of the most cosmopolitan cities in the Muslim world,[14] even though non-Muslims are prohibited from entering the city.[15][16]

"Mecca" is the familiar form of the English transliteration for the Arabic name of the city, although the official transliteration used by the Saudi government is Makkah, which is closer to the Arabic pronunciation.[17][18] The word "Mecca" in English has come to be used to refer to any place that draws large numbers of people, and because of this some English speaking Muslims have come to regard the use of this spelling for the city as offensive.[17] The Saudi government adopted Makkah as the official spelling in the 1980s, but is not universally known or used worldwide.[17] The full official name is Makkah al-Mukarramah (Arabic: مَـكَّـة الْـمُـكَـرَّمَـة) or Makkatu l-Mukarramah (Arabic: مَـكَّـةُ الْـمُـكَـرَّمَـة, [ˈmæk.kæl mʊkarˈrama, ˈmæk.kætʊl-]), which means "Mecca the Honored", but is also loosely translated as "The Holy City of Mecca".[17]

The ancient or early name for the site of Mecca is Bakkah (Arabic: بَـكَّـة,[19] also transliterated Baca, Baka, Bakah, Bakka, Becca, Bekka, etc.).[20][21][22] An Arabic language word, its etymology, like that of Mecca, is obscure.[23] Widely believed to be a synonym for Mecca, it is said to be more specifically the early name for the valley located therein, while Muslim scholars generally use it to refer to the sacred area of the city that immediately surrounds and includes the Ka‘bah (Arabic: كَـعْـبَـة,[19] Kaaba).[24] This form is used for the name Mecca in the Quran in 3:96, while the form Mecca is used in 48:24.[23][25] In South Arabic, the language in use in the southern portion of the Arabian Peninsula at the time of Muhammad, the b and m were interchangeable[citation needed]. Other references to Mecca in the Quran (6:92,[2] 42:5)[3] call it Umm al-Qurā (Arabic: أُمّ الْـقُـرَى), meaning "Mother of All Settlements"[25]/"mother of villages". Another name of Mecca is Ṫihāmah (Arabic: تِـهَـامَـة).[26]

Another name for Mecca, or the wilderness and mountains surrounding it, according to Arab and Islamic tradition, is Faran or Pharan, referring to the Desert of Paran mentioned in the Old Testament at Genesis 21:21.[27] Arab and Islamic tradition holds that the wilderness of Paran, broadly speaking, is the Tihamah and the site where Ishmael settled was Mecca.[27] Yaqut al-Hamawi, the 12th century Syrian geographer, wrote that Fārān was "an arabized Hebrew word, one of the names of Mecca mentioned in the Torah."[28]

Mecca is governed by the Municipality of Mecca, a municipal council of fourteen locally elected members headed by a mayor (called Al-Amin) appointed by the Saudi government. As of  MayÂ 2015[update], the mayor of the city was Dr. Osama bin Fadhel Al-Bar.[29][30]

Mecca is the capital of the Makkah Region, which includes neighboring Jeddah. The provincial governor was prince Abdul Majeed bin Abdulaziz Al Saud from 2000 until his death in 2007.[31] On 16 May 2007, prince Khalid bin Faisal Al Saud was appointed as the new governor.[32]

The early history of Mecca is still largely disputed, as there are no unambiguous references to it in ancient literature prior to the rise of Islam.[33] The Roman Empire took control of part of the Hejaz in 106 CE,[34] ruling cities such as Hegra (now known as Mada'in Saleh), located to the north of Mecca. Even though detailed descriptions were established of Western Arabia by Rome, such as by Procopius, there are no references of a pilgrimage and trading outpost such as Mecca.[35] The first direct mention of Mecca in external literature occurs in 741 CE, in the Byzantine-Arab Chronicle, though here the author places it in Mesopotamia rather than the Hejaz.[35]

Given the inhospitable environment[36] and lack of historical references in Roman, Persian and Indian sources, historians including Patricia Crone and Tom Holland have cast doubt on the claim that Mecca was a major historical trading outpost.[36][37]

The Greek historian Diodorus Siculus writes about Arabia in his work Bibliotheca historica, describing a holy shrine: "And a temple has been set up there, which is very holy and exceedingly revered by all Arabians".[38] Claims have been made this could be a reference to the Kaaba in Mecca. However, the geographic location Diodorus describes is located in northwest Arabia, around the area of Leuke Kome, closer to Petra and within the former Nabataean Kingdom and Rome's Arabia Petraea.[39][40]

Ptolemy lists the names of 50 cities in Arabia, one going by the name of "Macoraba". There has been speculation this is could be a reference to Mecca. However, due to the lack of a description or any other supporting literature, the claim is seen as contentious.[41]

In the Islamic view, the beginnings of Mecca are attributed to Ishmael's descendants. The Old Testament chapter Psalm 84:3â€“6, and a mention of a pilgrimage at the Valley of Baca, that Muslims see as referring to the mentioning of Mecca as Bakkah in Quran's Surah 3:96.[19] Some time in the 5th century, the Kaaba was a place of worship for the deities of Arabia's pagan tribes. Mecca's most important pagan deity was Hubal, which had been placed there by the ruling Quraysh tribe[42][43] and remained until the 7th century.

In the Sharḥ al- Asāṭīr, a  commentary on the Samaritan  midrashic chronology of the Patriarchs, of unknown date but probably composed in the tenth century C.E., it is claimed that Mecca was built by the sons of Nebaioth, the eldest son of Ishmael.[44][45][46]

In the 5th century, the Quraysh took control of Mecca, and became skilled merchants and traders. In the 6th century they joined the lucrative spice trade, since battles elsewhere were diverting trade routes from dangerous sea routes to more secure overland routes. The Byzantine Empire had previously controlled the Red Sea, but piracy had been increasing. Another previous route that ran through the Persian Gulf via the Tigris and Euphrates rivers was also being threatened by exploitations from the Sassanid Empire, and was being disrupted by the Lakhmids, the Ghassanids, and the Roman–Persian Wars. Mecca's prominence as a trading center also surpassed the cities of Petra and Palmyra.[47][48] The Sassanids however did not always pose a threat to Mecca, as in 575 CE they protected Mecca city from invasion by the Kingdom of Axum, led by its Christian leader Abraha. The tribes of southern Arabia asked the Persian king Khosrau I for aid, in response to which he came south to Arabia with foot-soldiers and a fleet of ships into Mecca. The Persian intervention prevented Christianity from spreading eastward into Arabia, and Mecca and the Islamic prophet Muhammad, who was at the time six years old in the Quraysh tribe, "would not grow up under the cross."[49]

By the middle of the 6th century, there were three major settlements in northern Arabia, all along the south-western coast that borders the Red Sea, in a habitable region between the sea and the great mountains to the east. Although the area around Mecca was completely barren, it was the wealthiest of the three settlements with abundant water via the renowned Zamzam Well and a position at the crossroads of major caravan routes.[50]

The harsh conditions and terrain of the Arabian peninsula meant a near-constant state of conflict between the local tribes, but once a year they would declare a truce and converge upon Mecca in an annual pilgrimage. Up to the 7th century, this journey was intended for religious reasons by the pagan Arabs to pay homage to their shrine, and to drink from the Zamzam Well. However, it was also the time each year that disputes would be arbitrated, debts would be resolved, and trading would occur at Meccan fairs. These annual events gave the tribes a sense of common identity and made Mecca an important focus for the peninsula.[51]

The Year of the Elephant is the name in Islamic history for the year approximately equating to 570 CE.  According to Islamic tradition, it was in this year that Muhammad was born.[52] The name is derived from an event said to have occurred at Mecca. According to early Islamic historians such as Ibn Ishaq, Abraha the Christian ruler of Yemen, which was subject to the Kingdom of Aksum of Ethiopia, built a great church at Sana'a known as al-Qullays in honor of the Aksumite king Negus. It gained widespread fame, even gaining the notice of the Byzantine Empire.[52] Abraha attempted to divert the pilgrimage of Arab people from Kaaba to al-Qullays and appointed a man named Muhammad ibn Khuza'i to Mecca and Tihamah as a king with a message that al-Qullays was both much better than other houses of worship and purer, having not been defiled by the housing of idols.[52] When Muhammad ibn Khuza'i got as far as the land of Kinana, the people of the lowland, knowing what he had come for, sent a man of Hudhayl called Ê¿Urwa bin Hayyad al-Milasi, who shot him with an arrow, killing him. His brother Qays who was with him fled to Abraha and told him the news, which increased his rage and fury and he swore to raid the Kinana tribe and destroy the temple. Ibn Ishaq further states that one of the men of the Quraysh tribe was angered by this, and going to Sana'a, slipped into the church at night and defiled it; it is widely assumed that they did so by defecating in it. Abraha[53][54] marched upon the Kaaba with a large army, which included one or more war elephants, intending to demolish it. When news of the advance of Abraha's army came, the Arab tribes of the Quraysh, Banu Kinanah, Banu Khuza'a and Banu Hudhayl united in defense of the Kaaba. A man from the Himyarite Kingdom was sent by Abraha to advise them that Abraha only wished to demolish the Kaaba and if they resisted, they would be crushed. Abdul Muttalib told the Meccans to seek refuge in the hills while he with some leading members of the Quraysh remained within the precincts of the Kaaba. Abraha sent a dispatch inviting Abdul-Muttalib to meet with Abraha and discuss matters. When Abdul-Muttalib left the meeting he was heard saying, "The Owner of this House is its Defender, and I am sure he will save it from the attack of the adversaries and will not dishonor the servants of His House." Abraha attacked Mecca  However, the lead elephant, known as Mahmud,[55] is said to have stopped at the boundary around Mecca and refused to enter. It has been theorized that an epidemic such as by smallpox could have caused such a failed invasion of Mecca.[56] The reference to the story in Qur'an is rather short. According to the Surah of Al-Fil, the next day, [as Abraha prepared to enter the city], a dark cloud of small birds sent by Allah appeared. The birds carried small rocks in their beaks, and bombarded the Ethiopian forces and smashed them like "eaten straw".[57]

Camel caravans, said to have first been used by Muhammad's great-grandfather, were a major part of Mecca's bustling economy. Alliances were struck between the merchants in Mecca and the local nomadic tribes, who would bring goods – leather, livestock, and metals mined in the local mountains – to Mecca to be loaded on the caravans and carried to cities in Shaam and Iraq.[58] Historical accounts also provide some indication that goods from other continents may also have flowed through Mecca. Goods from Africa and the Far East passed through en route to Syria including spices, leather, medicine, cloth, and slaves; in return Mecca received money, weapons, cereals and wine, which in turn were distributed throughout Arabia. The Meccans signed treaties with both the Byzantines and the Bedouins, and negotiated safe passages for caravans, giving them water and pasture rights. Mecca became the center of a loose confederation of client tribes, which included those of the Banu Tamim. Other regional powers such as the Abyssinian, Ghassan, and Lakhm were in decline leaving Meccan trade to be the primary binding force in Arabia in the late 6th century.[51]

Some Thamudic inscriptions which were discovered in the south Jordan contained names of some individuals such as ‘Abd Mekkat (Arabic: عَـبْـد مَـكَّـة, "Servant of Mecca").[59]

There were also some other inscriptions which contained personal names such as Makky (Arabic: مَـكِّي, "Meccan"), but Jawwad Ali from the University of Baghdad suggested that there's also a probability of a tribe named "Mecca".[60]

According to Islamic tradition, the history of Mecca goes back to Abraham (Ibrahim), who built the Kaaba with the help of his elder son Ishmael in around 2000 BCE, when the inhabitants of the site then known as Bakkah had fallen away from the original monotheism of Abraham through the influence of the Amalekites.[61]

Muhammad was born in Mecca in 570, and thus Islam has been inextricably linked with it ever since. He was born in a minor faction, the Hashemites, of the ruling Quraysh tribe. It was in Mecca, in the nearby mountain cave of Hira on Jabal al-Nour, that, according to Islamic tradition, Muhammad began receiving divine revelations from God through the Archangel Gabriel in 610 AD, and advocated his form of Abrahamic monotheism against Meccan paganism. After enduring persecution from the pagan tribes for 13 years, Muhammad emigrated (see Hijrah) in 622 with his companions, the Muhajirun, to Yathrib (later called Medina). The conflict between the Quraysh and the Muslims, however, continued: The two fought in the Battle of Badr, where the Muslims defeated the Quraysh outside Medina; while the Battle of Uhud ended indecisively. Overall, Meccan efforts to annihilate Islam failed and proved to be costly and unsuccessful. During the Battle of the Trench in 627, the combined armies of Arabia were unable to defeat Muhammad's forces.[62]

In 628, Muhammad and his followers wanted to enter Mecca for pilgrimage, but were blocked by the Quraysh. Subsequently, Muslims and Meccans entered into the Treaty of Hudaybiyyah, whereby the Quraysh promised to cease fighting Muslims and promised that Muslims would be allowed into the city to perform the pilgrimage the following year. It was meant to be a ceasefire for 10 years.  However, just two years later, the Quraysh violated the truce by slaughtering a group of Muslims and their allies. Muhammad and his companions, now 10,000 strong, marched into Mecca. However, instead of continuing their fight, the city of Mecca surrendered to Muhammad, who declared peace and amnesty for its inhabitants. The pagan imagery was destroyed by Muhammad's followers and the location Islamized and rededicated to the worship of God. Mecca was declared as the holiest site in Islam ordaining it as the center of Muslim pilgrimage, one of the faith's Five Pillars. Then, Muhammad returned to Medina, after assigning Akib ibn Usaid as governor of the city. His other activities in Arabia led to the unification of the peninsula.[47][62]

Muhammad died in 632, but with the sense of unity that he had passed on to his Ummah (Islamic nation), Islam began a rapid expansion, and within the next few hundred years stretched from North Africa into Asia and parts of Europe. As the Islamic Empire grew, Mecca continued to attract pilgrims from all across the Muslim world and beyond, as Muslims came to perform the annual Hajj pilgrimage.

Mecca also attracted a year-round population of scholars, pious Muslims who wished to live close to the Kaaba, and local inhabitants who served the pilgrims. Due to the difficulty and expense of the Hajj, pilgrims arrived by boat at Jeddah, and came overland, or joined the annual caravans from Syria or Iraq.

Mecca was never the capital of any of the Islamic states but Muslim rulers did contribute to its upkeep. During the reigns of Umar (634–644 CE) and Uthman ibn Affan (644–656) concerns of flooding caused the caliphs to bring in Christian engineers to build barrages in the low-lying quarters and construct dykes and embankments to protect the area round the Kaaba.[47]

Muhammad's migration to Medina shifted the focus away from Mecca. This focus moved still more when Ali, the fourth caliph, took power choosing Kufa as his capital. The Umayyad Caliphate moved the capital to Damascus in Syria and the Abbasid Caliphate to Baghdad, in modern-day Iraq, which remained the center of the Islamic Empire for nearly 500 years. Mecca re-entered Islamic political history during the Second Islamic Civil War, when it was held by Abd Allah ibn al-Zubayr, an early Muslim who opposed the Umayyad caliphs. The city was twice besieged by the Umayyads, in 683 and 692. For some time thereafter the city figured little in politics, remaining a city of devotion and scholarship governed by the Hashemite Sharifs.

In 930, Mecca was attacked and sacked by Qarmatians, a millenarian Ismaili Muslim sect led by Abū-Tāhir Al-Jannābī and centered in eastern Arabia.[63] The Black Death pandemic hit Mecca in 1349.[64]

In 1517, the Sharif, Barakat bin Muhammed, acknowledged the supremacy of the Ottoman Caliph but retained a great degree of local autonomy.[65]

In 1803 the city was captured by the First Saudi State,[66] which held Mecca until 1813. This was a massive blow to the prestige of the (Turkish) Ottoman Empire, which had exercised sovereignty over the holy city since 1517. The Ottomans assigned the task of bringing Mecca back under Ottoman control to their powerful Khedive (viceroy) of Egypt, Muhammad Ali Pasha. Muhammad Ali Pasha successfully returned Mecca to Ottoman control in 1813.

In 1818, followers of the Salafi juristic school were again defeated, but some of the Al Saud clan survived and founded the Second Saudi State that lasted until 1891 and led on to the present country of Saudi Arabia.

Mecca was regularly hit by cholera outbreaks. Between 1830 and 1930 cholera broke out among pilgrims at Mecca 27 times.[67]

Mecca in 1718

Mecca, ca. 1778

In the late 1880s

Bird's-eye view of Kaaba crowded with pilgrims in 1910

One of the world travelers to Mecca in the fifteenth century was Ibn Battuta. In his travels, he provides us with an important description of the city. Around the year 729, Ibn Battuta arrived in Mecca. Immediately when Battuta arrived in Mecca it felt like a holy sanctuary and thus he started the rites of the pilgrimage. He remained in Mecca for a couple of years. During Battuta's second year there, his caravan arrived "with a great quantity of alms for the support of those who were staying in Mecca and Medina" (p. 51). Giving these alms to the poor also helped to fulfill another pillar of faith, while he was also fulfilling the pillar of making the Pilgrimage to Mecca. While in Mecca, prayers were made for the King of Irak and then also for El Melik El Nasir. The prayers were made in the Temple of Mecca. This temple is very large, but was also destroyed once and was rebuilt a little bit smaller than the original. The temple also contained images of angels, prophets, Jesus, his mother Mary and many others. This temple is one of the most important parts of Mecca due to the fact that many people make the pilgrimage to Mecca for the purpose of going to the temple. The people of Mecca were also an important aspect of the village. They were described as being humble and kind, also willing to give a part of everything they had to someone who had nothing. The inhabitants of Mecca and the village itself was very clean. There was also a sense of elegance to the village. Ibn Battuta spent about three years in Mecca before he left with intentions of moving on to Yemen. Mecca nowadays is a lot different than Battuta saw it, but it still is a place of holiness. The city has become more advanced with new technology, but along with new skyscrapers and event centers, it still contains temples that are important for the pilgrimages to Mecca.[68]

In World War I, the Ottoman Empire was at war with Britain and its allies, having sided with Germany. It had successfully repulsed an attack on Istanbul in the Gallipoli Campaign and on Baghdad in the Siege of Kut. The British agent T. E. Lawrence conspired with the Ottoman governor Hussain bin Ali, the Sharif of Mecca. Hussein bin Ali revolted against the Ottoman Empire from Mecca, and it was the first city captured by his forces in the Battle of Mecca (1916). Sharif's revolt proved a turning point of the war on the eastern front. Sharif Hussein declared a new state, the Kingdom of Hejaz, and declared Mecca as the capital of the new kingdom.

News reports in November 1916[69] via contact in Cairo with returning Hajj pilgrims, said that with the Ottoman Turkish authorities gone, Mecca at Hajj 1916 was thankfully free of the previous massive extortion and illegal money-demanding by Turks who were agents of the Ottoman government.

Following the 1924 Battle of Mecca, the Sharif of Mecca was overthrown by the Saud family, and Mecca was incorporated into Saudi Arabia.[70]

Under Saudi rule, much of the historic city has been demolished as a result of construction programs â€“ see below. On 20 November 1979 two hundred armed Islamist dissidents led by Saudi preacher Juhayman al-Otaibi seized the Grand Mosque. They claimed that the Saudi royal family no longer represented pure Islam and that the Masjid al-Haram (The Sacred Mosque) and the Kaaba, must be held by those of true faith. The rebels seized tens of thousands of pilgrims as hostages and barricaded themselves in the mosque. The siege lasted two weeks, and resulted in several hundred deaths and significant damage to the shrine, especially the Safa-Marwa gallery. Pakistani forces carried out the final assault; they were assisted with weapons, logistics and planning by an elite team of French commandos from the French GIGN commando unit.[71]

Under Saudi rule, it has been estimated that since 1985 about 95% of Mecca's historic buildings, most over a thousand years old, have been demolished.[12][72]

Historic sites of religious importance which have been destroyed by the Saudis include five of the renowned "Seven Mosques" initially built by Muhammad's daughter and four of his "greatest Companions": Masjid Abu Bakr, Masjid Salman al-Farsi, Masjid Umar ibn al-Khattab, Masjid Sayyida Fatima bint Rasulullah and Masjid Ali ibn Abu Talib.[73]

It has been reported that there are now fewer than 20 structures remaining in Mecca that date back to the time of Muhammad. Other buildings that have been destroyed include the house of Khadijah, the wife of Muhammad, demolished to make way for public lavatories; the house of Abu Bakr, Muhammad's companion, now the site of the local Hilton hotel; the house of Muhammad's grandson Ali-Oraid and the Mosque of abu-Qubais, now the location of the King's palace in Mecca; Muhammad's birthplace, demolished to make way for a library; and the Ottoman-era Ajyad Fortress, demolished for construction of the Abraj Al Bait Towers.[74]

The reason for much of the destruction of historic buildings has been for the construction of hotels, apartments, parking lots, and other infrastructure facilities for Hajj pilgrims. However, many have been destroyed without any such reason. For example, when the house of Ali-Oraid was discovered, King Fahd himself ordered that it be bulldozed lest it should become a pilgrimage site.[72]

The pilgrimage to Mecca attracts millions of Muslims from all over the world. There are two pilgrimages: the Hajj and the Umrah. The Hajj, the 'greater' pilgrimage is performed annually in Mecca and nearby sites. During the Hajj, several million people of varying nationalities worship in unison. Every adult, healthy Muslim who has the financial and physical capacity to travel to Mecca and can make arrangements for the care of his/her dependents during the trip, must perform the Hajj at least once in a lifetime. Umrah, the lesser pilgrimage, is not obligatory, but is recommended in the Qur'an.[75] Often, they perform the Umrah while visiting Al-Haram Mosque.

Mecca has been the site of several incidents and failures of crowd control because of the large numbers of people who come to make the Hajj.[76][77][78] For example, on 2 July 1990, a pilgrimage to Mecca ended in tragedy when the ventilation system failed in a crowded pedestrian tunnel and 1,426 people were either suffocated or trampled to death in a stampede.[79] On 24 September 2015, 700 pilgrims were killed in a stampede at Mina during the stoning-the-Devil ritual at Jamarat.[80]

Mecca is at an elevation of 277 m (909 ft) above sea level, and approximately 80 km (50 mi) inland from the Red Sea.[50] Central Mecca lies in a corridor between mountains, which is often called the "Hollow of Mecca". The area contains the valley of Al Taneem, the Valley of Bakkah and the valley of Abqar.[47][81] This mountainous location has defined the contemporary expansion of the city. The city centers on the Masjid al-Haram area, which is lower than most of the city. The area around the mosque is the old city. The main avenues are Al-Mudda'ah and Sūq al-Layl to the north of the mosque, and As-Sūg Assaghīr to the south. As the Saudis expanded the Grand Mosque in the center of the city, hundreds of houses were replaced by wide avenues and city squares. Traditional homes are built of local rock and are generally two to three stories. The total area of Mecca today is over 1,200 km2 (460 sq mi).[82]

In pre-modern Mecca, the city used a few chief sources of water. The first were local wells, such as the Zamzam Well, that produced generally brackish water. The second source was the spring of Ayn Zubayda. The sources of this spring are the mountains of J̲abal Saʿd (Jabal Sa'd) and Jabal Kabkāb, which are a few kilometers east of Jabal Arafa or about 20 km (12 mi) southeast of Mecca. Water was transported from it using underground channels. A very sporadic third source was rainfall which was stored by the people in small reservoirs or cisterns. The rainfall, scant as it is, also presents the threat of flooding and has been a danger since earliest times. According to Al-Kurdī, there had been 89 historic floods by 1965, including several in the Saudi period. In the last century the most severe flood was in 1942. Since then, dams have been build to ameliorate this problem.[81]

Mecca features a hot desert climate. Like most Saudi Arabian cities, Mecca retains warm to hot temperatures even in winter, which can range from 18 °C (64 °F) at night to 30 °C (86 °F) in the afternoon. Summer temperatures are extremely hot and break the 40 °C (104 °F) mark in the afternoon dropping to 30 °C (86 °F) in the evening. Rain usually falls in Mecca in small amounts scattered between November and January:

Mecca houses Al-Haram Mosque, the largest mosque in the world. The mosque surrounds the Kaaba, which Muslims turn towards while offering daily prayer. This mosque is also commonly known as the Ḥaram or Grand Mosque.[88]

As mentioned above, because of the Wahhabist hostility to reverence being paid to historic and religious buildings, Mecca has lost most of its heritage in recent years and few buildings from the last 1,500 years have survived Saudi rule.[72]

Expansion of the city is ongoing and includes the construction of 601 m (1,972 ft) tall Abraj Al Bait Towers across the street from the Masjid al-Haram.[89] The towers were the third tallest building in the world when completed in 2012. The construction of the towers involved the demolition of the Ajyad Fortress, which in turn sparked a dispute between Turkey and Saudi Arabia.[90]

The Zamzam Well is home to a celebrated water spring. The Qishla of Mecca was an Ottoman castle facing the Grand Mosque and defending the city from attack. However, the Saudi government removed the structure to give space for hotels and business buildings near to the Grand Mosque.[91] Ḥirā’ (Arabic: حِـرَاء) is a cave near Mecca, on the mountain named Jabal an-Nūr (Arabic: جَـبَـل الـنُّـوْر, "Mountain of Light") in the region of Tihamah of present-day Saudi Arabia. It is notable for being the location where Muhammad received his first revelations from God through the angel Jibrā’īl (Arabic: جِـبْـرَائِـيْـل), who known as Gabriel to Christians.[92][93]

The Qur'an Gate, located on the Jeddah-Mecca Highway, marks the boundary of the area where non-Muslims are prohibited to enter. It is the entrance to Makkah and the birthplace of Muhammad. The gate was designed in 1979 by an Egyptian architect, Samir Elabd, for the architectural firm IDEA Center. The structure is that of a book, representing the Qur'an,  sitting on a rehal, or book stand.[94]

The Meccan economy has been heavily dependent on the annual pilgrimage. As one academic put it, "[Meccans] have no means of earning a living but by serving the hajjis." Income generated from the Hajj, in fact, not only powers the Meccan economy but has historically had far-reaching effects on the economy of the entire Arabian Peninsula. The income was generated in a number of ways. One method was taxing the pilgrims. Taxes especially increased during the Great Depression, and many of these taxes existed as late as 1972. Another way the Hajj generates income is through services to pilgrims. For example, the Saudi national airline, Saudia, generates 12% of its income from the pilgrimage. Fares paid by pilgrims to reach Mecca by land also generate income; as do the hotels and lodging companies that house them.[81]

The city takes in more than $100 million, while the Saudi government spends about $50 million on services for the Hajj. There are some industries and factories in the city, but Mecca no longer plays a major role in Saudi Arabia's economy, which is mainly based on oil exports.[95] The few industries operating in Mecca include textiles, furniture, and utensils.  The majority of the economy is service-oriented.

Nevertheless, many industries have been set up in Mecca. Various types of enterprises that have existed since 1970: corrugated iron manufacturing, copper smithies, carpentry shops, upholstering establishments, vegetable oil extraction plants, sweets manufacturies, flour mills, bakeries, poultry farms, frozen food importing, photography processing, secretarial establishments, ice factories, bottling plants for soft drinks, barber shops, book shops, travel agencies and banks.[81]

The city has grown substantially in the 20th and 21st centuries, as the convenience and affordability of jet travel has increased the number of pilgrims participating in the Hajj. Thousands of Saudis are employed year-round to oversee the Hajj and staff the hotels and shops that cater to pilgrims; these workers in turn have increased the demand for housing and services. The city is now ringed by freeways, and contains shopping malls and skyscrapers.[96]

Health care is provided by the Saudi government free of charge to all pilgrims. There are ten hospitals in Mecca:[97]

There are also many walk-in clinics available for both residents and pilgrims.

Mecca's culture has been affected by the large number of pilgrims that arrive annually, and thus boasts a rich cultural heritage. As a result of the vast numbers of pilgrims coming to the city each year, Mecca has become by far the most diverse city in the Muslim world. In contrast to the rest of Saudi Arabia, and particularly Najd, Mecca has, according to The New York Times, become "a striking oasis" of free thought and discussion and, also, of "unlikely liberalism" as "Meccans see themselves as a bulwark against the creeping extremism that has overtaken much Islamic debate".[14]

The first press was brought to Mecca in 1885 by Osman Nuri Pasha, an Ottoman Wāli. During the Hashemite period, it was used to print the city's official gazette, al-Qibla. The Saudi regime expanded this press into a larger operation, introducing the new Saudi official gazette Umm al-Qurā. Henceforth presses and printing techniques were introduced in the city from around the Middle East, mostly via Jeddah.[81]

Mecca owns its hometown paper, Al Nadwa. However, other Saudi and international newspapers are also provided in Mecca such as the Saudi Gazette, Al Madinah, Okaz and Al-Bilad. The first three are Mecca's (and other Saudi cities') primary newspapers focusing mainly on issues that affect the city, with over a million readers.

Many television stations serving the city area include Saudi TV1, Saudi TV2, Saudi TV Sports, Al-Ekhbariya, Arab Radio and Television Network and various cable, satellite and other specialty television providers.

In pre-modern Mecca the most common sports were impromptu wrestling and foot races.[81] Football is the most popular sport in Mecca, the city hosting some of the oldest sport clubs in Saudi Arabia such as, Al-Wahda FC (established in 1945). King Abdulaziz Stadium is the largest stadium in Mecca with capacity of 38,000.[98]

As in other Arabian cities, Kabsa (a spiced dish of rice and meat) is the most traditional lunch but the Yemeni mandi (a dish of rice and tandoori cooked meat) is also popular. Grilled meat dishes such as shawarma (flat-bread meat sandwich), kofta (meatballs) and kebab[clarification needed] are widely sold in Mecca. During Ramadan, fava beans in olive oil and samosas are the most popular dishes and are eaten at dusk. These dishes are almost always found in Lebanese, Syrian, and Turkish restaurants.[citation needed]

The mixture of different ethnicities and nationalities amongst Meccan residents has significantly impacted Mecca's traditional cuisine.[citation needed] The city has been described as one of the most cosmopolitan Islamic cities, with an international cuisine.[99]

Traditionally during the month of Ramadan, men (known as Saggas) provided mineral water and fruit juice for Muslims breaking their fast at dusk. Today, Saggas make money providing sweets such as baklava and basbosa along with fruit juice drinks.[citation needed]

In the 20th century, many fast-food chains opened franchises in Mecca, catering to locals and pilgrims alike.[100] Exotic foods, such as fruits from India and Japan, are often brought by the pilgrims.[101]

Population density in Mecca is very high. Most long-term residents of Mecca live in the Old City, and many work in the industry known locally as the Hajj Industry. Iyad Madani, Saudi Arabia's minister for Hajj, was quoted as saying, "We never stop preparing for the Hajj."[102] Year-round, pilgrims stream into the city to perform the rites of Umrah, and during the last weeks of Dhu al-Qi'dah, on average 4 million Muslims arrive in the city to take part in the rites known as Hajj.[103]

Pilgrims are from varying ethnicities and backgrounds, mainly Central Asia, South Asia, Southeast Asia, Europe, the Middle East, and Africa. Many of these pilgrims have remained and become residents of the city. The Burmese are an older, more established community who number roughly 250,000.[104] Adding to the Hajj-related diversity, the oil-boom of the past 50 years has brought hundreds of thousands of working immigrants.

Non-Muslims are not permitted to enter Mecca under Saudi law,[15] and using fraudulent documents to do so may result in arrest and prosecution.[105] The prohibition extends to Ahmadis, as they are considered non-Muslims.[106] Nevertheless, many non-Muslims and Ahmadis have visited the city. The first such recorded example of non-Muslims is that of Ludovico di Varthema of Bologna in 1503.[107] Guru Nanak Sahib, the founder of Sikhism, visited Mecca in December 1518.[108] One of the most famous was Richard Francis Burton,[109] who traveled as a Qadiriyyah Sufi from Afghanistan in 1853. The Saudi government supports their position using[citation needed] Sura 9:28 from the Qur'an:
"O ye who believe! Truly the Pagans are unclean; so let them not, after this year of theirs, approach the Sacred Mosque."

Formal education started to be developed in the late Ottoman period continuing slowly into and Hashimite times. The first major attempt to improve the situation was made by a Jeddah merchant, Muhammad ʿAlī Zaynal Riḍā, who founded the Madrasat al-Falāḥ in Mecca in 1911–12 that cost £400,000.[81]

The school system in Mecca has many public and private schools for both males and females. As of 2005, there were 532 public and private schools for males and another 681 public and private schools for female students.[110] The medium of instruction in both public and private schools is Arabic with emphasis on English as a second language, but some private schools founded by foreign entities such as International schools use the English language for medium of instruction. They also allow mixing between males and females while other schools do not.

For higher education, the city has only one university, Umm Al-Qura University, which was established in 1949 as a college and became a public university in 1979.[citation needed]

In 2010, the Mecca area became an important site for paleontology with respect to primate evolution, with the discovery of a Saadanius fossil. Saadanius is considered to be a primate closely related to the common ancestor of the Old World monkeys and apes. The fossil habitat, near what is now the Red Sea in western Saudi Arabia, was a damp forest area between 28 million and 29 million years ago.[111]

Paleontologists involved in the research hope to find further fossils in the area.[112]

Telecommunications in the city were emphasized early under the Saudi reign.  King Abdul Aziz Al-Saud (Ibn Saud) pressed them forward as he saw them as a means of convenience and better governance.  While in King Husayn's time there were about 20 telephones in the entire city; in 1936 the number jumped to 450, totalling about half the telephones in the country.  During that time, telephone lines were extended to Jeddah and Taâ€™if, but not to the capital Riyadh.  By 1985, Mecca, like other Saudi cities, possessed modern telephone, telex, radio and television communications.[81]

Limited radio communication was established within the Kingdom under the Hashimites.  In 1929, wireless stations were set up in various towns of the region, creating a network that would become fully functional by 1932.  Soon after World War II, the existing network was greatly expanded and improved.  Since then, radio communication has been used extensively in directing the pilgrimage and addressing the pilgrims.  This practice started in 1950, with the initiation of broadcasts the Day of Arafa, and increased until 1957, at which time Radio Makka became the most powerful station in the Middle East at 50 kW.  Later, power was increased to 450 kW.  Music was not immediately broadcast, but gradually introduced.[81]

Mecca has only the small Mecca East Airport with no airline service, so Mecca is served by King Abdulaziz International Airport (IATA: JED, ICAO: OEJN) located at Jeddah, about 100 kilometres from the city centre. To cater the large number of Hajj pilgrims, this airport has a specifically built Hajj terminal which can accommodate 47 planes simultaneously and it can receive 3,800 pilgrims per hour during the Hajj season.[113]

Al Mashaaer Al Mugaddassah Metro is a metro line in Mecca opened in 13 November 2010.[114] This 18.1 kilometer elevated metro transports pilgrims to holy sites Mount Arafat, Muzdalifah and Mina in the city during hajj reducing the congestion on the roads.[115]

Mecca Metro, officially known as Makkah Mass Rail Transit, is a planned four-line metro system for the city.[116] This will be in addition to[116] the Al Mashaaer Al Mugaddassah Metro which carries pilgrims during Hajj.

A high speed inter-city rail line (Haramain High Speed Rail Project also known as the "Western Railway"), is under construction in Saudi Arabia. It will link along 444 kilometres (276 mi), the Muslim holy cities of Medina and Mecca via King Abdullah Economic City, Rabigh, Jeddah and King Abdulaziz International Airport.[117] This rail line is planned to provide a safe and comfortable transport in 320 kilometres per hour (200 mph) electric trains in-turn reducing the travel time to less than two hours between Mecca and Medina.[118] It will be built by a business consortium from Spain.[119]

Some of the intercity highways which connects the city of Mecca are:[120][121]