Where is the worlds tallest building?

The buildings that were the tallest secular skyscrapers, which excludes religious buildings, were:
The list of tallest buildings is based on the default metric of the Council on Tall Buildings and Urban Habitat (CTBUH), that of measuring to the highest architectural element. Other criteria would generate a different list. Shanghai World Financial Center is not on the above list, but it surpassed Taipei 101 in 2008 to become the building with the highest occupied floor. Using the criteria of highest tip (including antennae), the World Trade Center in New York City was the world's tallest building from 1972 to 2000, until the Sears Tower in Chicago (which already had a higher occupied floor than the World Trade Center) had its antenna extended to give that building the world's tallest tip; a title it held until the 2010 completion of Burj Khalifa. Petronas Towers and Taipei 101 were never the world's tallest buildings by the highest–tip criteria.

History of the world's tallest buildings

The tallest building in the world, as of 2022, is Burj Khalifa. The title of "world's tallest building" has been borne by various buildings, such as the Rouen Cathedral and the Empire State Building.

The skyscraper was invented in Chicago in 1884 when the Home Insurance Building was constructed using a steel-frame with curtain walls instead of load-bearing walls. For the next hundred years, the world's tallest building was always in the United States with New York City accumulating 86 years, and Chicago accumulating 30 years. After just over a century (1885–1998), the distinction moved to the Eastern Hemisphere. Malaysia was the first country to break the United States' record of constructing the tallest buildings in the world when the Petronas Twin Towers were completed in 1998. Taiwan's Taipei 101 was the next building to hold the record, beginning in 2004.

Before the modern skyscraper era, many Christian churches and cathedrals, built mainly in England and Germanic territories between 1250–1894, comprised the tallest buildings in the world. Before the 13th century, the tallest buildings in the world cannot be conclusively determined. For instance, the Lighthouse of Alexandria (completed about 280 BC) has been estimated to be tall, but its true height is not known. For thousands of years, the Great Pyramid in Egypt was the tallest "structure" in the world, but the Great Pyramid is not considered a building since it is not habitable.

The earliest structures now known to be the tallest in the world were the Egyptian pyramids, with the Great Pyramid of Giza, at an original height of, being the tallest man-made structure in the world for over 3,800 years, until the construction of Lincoln Cathedral in 1300. From then until the completion of the Washington Monument (capped in 1884) the world's tallest buildings were churches or cathedrals. Later, the Eiffel Tower and, still later, some radio masts and television towers were the world's tallest structures.

However, though all of these are "structures", some are not "buildings" in the sense of being regularly inhabited or occupied. It is in this sense of being regularly inhabited or occupied that the term "building" is generally understood to mean when determining what is the world's tallest building. The non-profit international organization Council on Tall Buildings and Urban Habitat (CTBUH), which maintains a set of criteria for determining the height of tall buildings, defines a "building" as "(A) structure that is designed for residential, business or manufacturing purposes" and "has floors".

Tall churches and cathedrals occupy a middle ground: their lower areas are regularly occupied, but much of their height is in bell towers and spires which are not. Whether a church or cathedral is a "building" or merely a "structure" for the purposes of determining the title of "world's tallest building" is a subjective matter of definition (this article treats churches and cathedrals as buildings).

The Council on Tall Buildings and Urban Habitat based in Chicago uses three different criteria for determining the height of a tall building, each of which may give a different result. "Height of the highest floor" is one criterion, and "height to the top of any part of the building" is another, but the default criterion used by the CTBUH is "height of the architectural top of the building", which includes spires but not antennae, masts or flag poles.

Hwangnyongsa, or Hwangnyong Temple (also spelled Hwangryongsa) is the name of a former Buddhist temple in the city of Gyeongju, South Korea. Completed in the 7th century, the enormous 9-story structure was built entirely with wood with interlocking design with no iron nails. It had a standing total height of 68 m (223 ft) or 80 m (262 ft), making it the tallest structure in East Asia and the tallest wooden structure in the world at the time of its construction.

From the 13th century until 1894, the world's tallest building was always a church or cathedral. Old St Paul's Cathedral with its spire was completed in the 13th century. The central spire of Lincoln Cathedral surpassed Old St Paul's in the early 14th century. The Lincoln Cathedral's spire collapsed in 1549, beginning a long interval where the status of world's tallest building was borne by shorter buildings. St. Mary's Church in Stralsund became the world's tallest building after the collapse of Lincoln Cathedral's spire. The central tower of St. Pierre's Cathedral was tallest from 1569 until it collapsed in 1573, making St. Mary's the tallest once again. In 1647, the bell tower of St. Mary's burned down, making the shorter Strasbourg Cathedral the world's tallest building.

It was not until the completion of the Ulm Minster in 1890 that the world's tallest building was again also the tallest building ever constructed, surpassing the original configuration of Lincoln Cathedral.
* – Also set record at time of completion as tallest building ever built.

The height of Lincoln Cathedral is disputed by some, but accepted by most sources. The completion date for the spire is given as 1311 rather than 1300 by some sources. Also the height of the spire of Old St Paul's Cathedral, destroyed by lightning in 1561, is disputed, for example Christopher Wren (1632–1723) judged that an overestimate and gave a height of.

The spire of Mole Antonelliana in Turin, completed in 1889, is claimed to have been tall; however, the upper part of the structure was destroyed by a 1953 tornado and rebuilt. If the original spire was as tall as is claimed, then the Mole Antonelliana was the world's tallest building from 1889 to 1908, surpassing Philadelphia City Hall by.

Since 2010, Burj Khalifa has been the tallest building by any criteria. It has the highest architectural element, tip and occupied floor, and is indeed the tallest structure of any kind ever built, surpassing the (now destroyed) Warsaw radio mast.

Since the completion of the Washington Monument in 1884, the world's tallest building has not usually also been the world's tallest "structure". The exceptions are 1930–1954, when the Chrysler Building and then the Empire State building surpassed the Eiffel Tower (to be surpassed in turn by a succession of broadcast masts, starting with the Griffin Television Tower in Oklahoma), and from 2010 with the completion of Burj Khalifa.

In this chart, time progresses from right to left. Note the early buildings that lost the title as their spires collapsed.
After the construction of the Home Insurance Building in Chicago in the 19th century, the incrementation in the height of skyscrapers began with the construction of the Chrysler Building, followed by the Empire State Building, in New York City. The Chrysler Building was the first building in the world to break the barrier, and the Empire State Building was the first building to have more than 100 floors. It stands at and has 102 floors. The next tallest skyscraper was the World Trade Center, which was completed in 1971. The north tower was and the south tall. It surpassed the height of the Empire State Building by. Two years later the Sears Tower was built in Chicago, standing at with 110 floors, surpassing the height of the World Trade Center by. The Petronas Towers rose 10 meters above the Sears Tower, standing at a height of and each having 88 floors.

In 2004, the construction of Taipei 101 brought the height of skyscrapers to a new level, standing at with 101 floors. It is taller than the previous record holders, the Petronas Towers. Burj Khalifa surpassed the height of Taipei 101 by in 2009, making it 60% taller. It has broken several skyscraper records, and it is almost twice as tall as the Empire State Building. Burj Khalifa has also broken the record of the world's tallest structure.Since the early skyscraper boom that took place in North America, the significant number of skyscrapers in North America have dominated the 100 tallest buildings in the world. In 1930, 99 of the 100 tallest buildings in the world were located in North America. In the future, this percentage is expected to decline to only 22 percent. The predominance of skyscrapers in North America is decreasing due to skyscraper construction in other parts of the world, especially in Asia.

In Asia, there has been an increase in the number of supertall skyscrapers beginning with the construction of Petronas Twin Towers. There are currently sixty buildings in the world's 100 tallest that are located in Asia (including the Middle East).

Since the skyscraper era began, the great majority of skyscrapers were used predominantly as office space. From 1930 to 2000, the percentage of office towers never fell below 86 percent, but in the future it is expected to be as low as 46 percent. By 2010, less than half of the 100 tallest buildings in the world were office towers with the majority utilized as residential and mixed use. Presently, only four out of the ten tallest buildings in the world, and twenty eight out of the fifty tallest in the world, are used primarily as offices.

A mixed-use tall building contains two or more functions (uses), where each of the functions occupies a significant proportion of the tower's total space. Support areas such as car parks and mechanical plant space do not contribute towards mixed-use status.

Skyscrapers used primarily or exclusively as hotels or residential space are generally shorter than office and mixed-use buildings, with only a few supertall buildings of the residential or hotel types among the 100 tallest skyscrapers. The tallest completed residential building (minimum 85% residential) is 432 Park Avenue in New York City, followed by the Princess Tower and 23 Marina, both in Dubai. The tallest completed hotels (primarily hotel space) are the Gevora Hotel, the JW Marriott Marquis Dubai twin towers, the Rose Tower, and the Burj Al Arab, all located in Dubai.

Dubai, the largest city in the United Arab Emirates, is home to many modern high-rises, 88 of which stand taller than. The tallest building in Dubai is the Burj Khalifa, which rises and contains 161 floors. The tower has stood as both the tallest building in the world and the tallest man-made structure of any kind in the world since its completion in January 2010. The second-tallest building in Dubai is the Marina 101, which also stands as the world's tallest residential skyscraper. The skyscrapers of Dubai are, for the most part, clustered in three different locations. The land along Sheikh Zayed Road was the first to develop, followed by the Dubai Marina neighborhood and the Business Bay district.

List of tallest buildings in Dubai

Overall, Dubai has 18 completed and topped-out buildings that rise at least in height, which is more than any other city in the world. Dubai has 73 completed and topped-out buildings that rise at least in height, again which is more than any other city in the world. Based on the average height of the ten tallest completed buildings, Dubai has the tallest skyline in the Middle East and the world., the skyline of Dubai is ranked sixth in the world with 248 buildings rising at least in height.

The history of skyscrapers in Dubai began with the construction of Dubai World Trade Centre in 1979, which is usually regarded as the first high-rise in the city. At the time of its completion, it also stood as the tallest building in the Middle East. Since 1999, and especially from 2005 onwards, Dubai has been the site of an extremely large skyscraper building boom, with all 73 of its buildings over tall completed after 1999. In less than ten years, the city has amassed one of the largest skylines in the world; it is now home to the world's tallest building, the world's tallest residence, and the world's second tallest hotel., 363 new skyscrapers are under construction in Dubai; additionally, there are over 640 active high-rise developments that have been proposed for construction in the city.

This list ranks completed and topped out Dubai skyscrapers that stand at least tall, based on standard height measurement. This includes spires and architectural details but does not include antenna masts. An equal sign (=) following a rank indicates the same height between two or more buildings. The "Year" column indicates the year in which a building was completed.
* indicates building is still under construction, but has been topped out

This is the list of buildings that are currently under construction in Dubai and are expected to rise to a height of at least. Buildings under construction that have already been topped out are also included, as are those whose construction has been suspended.
*Table entries with dashes (—) indicate that information regarding building dates of completion has not yet been released.

This table lists buildings that were at one time under construction in Dubai and were expected to rise at least in height, but are now on hold. While not officially cancelled, construction has been suspended on each development.
This table lists buildings that are approved for construction in Dubai and are expected to rise at least in height.
*Table entries with dashes (—) indicate that information regarding building dates of completion has not yet been released.
This table lists buildings that are proposed for construction in Dubai and are expected to rise at least in height.
*Table entries with dashes (—) indicate that information regarding building heights and/or dates of completion has not yet been released.

This is a list of the buildings that once were the tallest in Dubai. Despite Dubai's recent major skyscraper boom, there are only seven buildings on the list.

The international non-profit organization Council on Tall Buildings and Urban Habitat (CTBUH) was formed in 1969 and announces the title of "The World's Tallest Building" and sets the standards by which buildings are measured. It maintains a list of the 100 tallest completed buildings in the world. The organization currently ranks Burj Khalifa in Dubai as the tallest at. The CTBUH only recognizes buildings that are complete however, and some buildings included within the lists in this article are not considered finished by the CTBUH.

List of tallest buildings

This list of tallest buildings includes skyscrapers with continuously occupiable floors and a height of at least. Non-building structures, such as towers, are not included in this list (see list of tallest buildings and structures).

In 1996, as a response to the dispute as to whether the Petronas Towers or the Sears Tower was taller, the council listed and ranked buildings in four categories:

Spires are considered integral parts of the architectural design of buildings, to which changes would substantially change the appearance and design of the building, whereas antennas may be added or removed without such consequences. The Petronas Towers, with their spires, are thus ranked higher than the Willis Tower (formerly the Sears Tower) with its antennas, despite the Petronas Towers' lower roofs and lower highest point.

Until 1996, the world's tallest building was defined by the height to the top of the tallest architectural element, including spires but not antennae. This led to a rivalry between the Bank of Manhattan Building and the Chrysler Building. The Bank of Manhattan Building (aka 40 Wall Street) employed only a short spire and was tall and had a much higher top occupied floor (the second category in the 1996 criteria for tallest building). In contrast, the Chrysler Building employed a very large spire secretly assembled inside the building to claim the title of world's tallest building with a total height of, although it had a lower top occupied floor and a shorter height when both buildings' spires were excluded.

Upset by Chrysler's victory, Shreve & Lamb, the consulting architects of the Bank of Manhattan Building, wrote a newspaper article claiming that their building was actually the tallest, since it contained the world's highest usable floor, at. They pointed out that the observation deck in the Bank of Manhattan Building was nearly above the top floor in the Chrysler Building, whose surpassing spire was strictly ornamental and inaccessible.

At present, the Burj Khalifa tops the list by some margin, regardless of which criterion is applied.

, this list includes all 64 buildings (completed and architecturally topped out) which reach a height of or more, as assessed by their highest architectural feature. Of these, 27 (48%) are in China. Six of the last seven buildings to have held the record as 'tallest building' are still found in the list, with the exception being the North Tower of the original World Trade Center at after its destruction in the September 11 attacks of 2001. If the twin towers were still standing today they would occupy numbers 24 and 25 on the list (or 23 and 24 since it can be assumed the rebuilt One World Trade Center would have never been built).

This measurement disregards distinctions between architectural and non-architectural extensions, and simply measures to the highest point. This measurement is useful for air traffic obstacle determinations, and is also a wholly objective measure. However, this measurement includes extensions that are easily added, removed, and modified from a building and are independent of the overall structure.

This measurement only recently came into use, when the Petronas Towers passed the Sears Tower (now called Willis Tower) in height. The former was considered taller because its spires were considered architectural, while the latter's antennae were not. This led to the split of definitions, with the Sears Tower claiming the lead in this and the height-to-roof (now highest occupied floor) categories, and with the Petronas claiming the lead in the architectural height category.

If the World Trade Center towers were still standing today they would occupy numbers 11 (North Tower at ) and 31 on the list (or 10 and 30 since it can be assumed the rebuilt One World Trade Center would have never been built).

This height is measured from the level of the lowest, significant, open-air, pedestrian entrance to the highest occupied floor within the building.

This is a list of buildings taller than that are currently under construction. More than half of the buildings are located in China.

The following list shows the tallest completed buildings located in each continent listed by greatest to least height (click on name of continent for continent-specific list):

The world's tallest artificial structure is the Burj Khalifa in Dubai (of the United Arab Emirates). The building gained the official title of "Tallest Building in the World" and the tallest self-supported structure at its opening on January 9, 2010. The second-tallest self-supporting structure and the tallest tower is the Tokyo Skytree. The tallest guyed structure is the KVLY-TV mast.

List of tallest buildings and structures

The Council on Tall Buildings and Urban Habitat, an organization that certifies buildings as the "World's Tallest", recognizes a building only if at least 50% of its height is made up of floor plates containing habitable floor area. Structures that do not meet this criterion, such as the CN Tower, are defined as "towers".

There are dozens of radio and television broadcasting towers which measure over 600 metres (about 2,000 ft) in height, and only the tallest are recorded in publicly available information sources.

The assessment of the height of artificial structures has been controversial. Various standards have been used by different organizations which has meant that the title of world's tallest structure or building has changed depending on which standards have been accepted. The Council on Tall Buildings and Urban Habitat has changed its definitions over time. Some of the controversy regarding the definitions and assessment of tall structures and buildings has included the following:

Within an accepted definition of a building further controversy has included the following factors:

This category does not require the structure to be "officially" open but does require it to be "topped out".

The tallest artificial structure is Burj Khalifa, a skyscraper in Dubai that reached in height on January 17, 2009. By April 7, 2008 it had been built higher than the KVLY-TV mast in North Dakota, USA. That September it officially surpassed Poland's Warsaw radio mast, which stood from 1974 to 1991, to become the tallest structure ever built. Guyed lattice towers such as these masts had held the world height record since 1954.

The Petronius Platform stands off the sea floor leading some, including "Guinness World Records" 2007, to claim it as the tallest freestanding structure in the world. However, it is debated whether underwater height should be counted, in the same manner as height below ground is ignored on buildings. The Troll A platform is, without any part of that height being supported by wires. The tension-leg type of oil platform has even greater below-water heights with several examples more than deep. However, these platforms are not considered constant structures as the vast majority of their height is made up of the length of the tendons attaching the floating platforms to the sea floor. Despite this, "Guinness World Records" 2009 listed the Ursa tension leg platform as the tallest structure in the world with a total height of. The Magnolia Tension-leg Platform in the Gulf of Mexico is even taller with a total height of.

Taipei 101 in Taipei, Taiwan, set records in three of the four skyscraper categories at the time it opened in 2004; at the time the Burj Khalifa opened in 2010 it remained the world's tallest inhabited building as measured to its architectural height (spire). The height of its roof and highest occupied floor had been surpassed by the Shanghai World Financial Center with corresponding heights of. Willis Tower (formerly Sears Tower) was the highest in the final category: the greatest height to top of antenna of any building in the world at.

Burj Khalifa broke the height record in all four categories for completed buildings.

Due to the disagreements over how to measure height and classify structures, engineers have created various definitions for categories of buildings and other structures. One measure includes the absolute height of a building, another includes only spires and other permanent architectural features, but not antennas. The tradition of including the spire on top of a building and not including the antenna dates back to the rivalry between the Chrysler Building and 40 Wall Street. A modern-day example is that the antenna on top of Willis Tower (formerly Sears Tower) is not considered part of its architectural height, while the spires on top of the Petronas Twin Towers are counted.

"Note:" The following table is a list of the tallest completed structure in each of the structural categories below. For a list of structures by function see the list later in the article. There can only be one structure in each category, unless the tallest is the same for more than one structure in the same category.

There are some destroyed architectural structures which were taller than the tallest existing structure of their type. There are also destroyed structures omitted from this list that had been surpassed in height prior to being destroyed.

* "Mixed-use" is defined as having three or more real estate uses (such as retail, office, hotel, etc.) that are physically and functionally integrated in a single property and are mutually supporting.

Up until the late 1990s, the definition of “tallest building” was not altogether clear. It was generally understood to be the height of the building to the top of its architectural elements including spires, but not including "temporary" structures (such as antennas or flagpoles), which could be added or changed relatively easily without requiring major changes to the building's design. Other criteria for height measurement generally were not considered, which occasionally caused some controversy.

One historic case involved the building now famous for the Times Square Ball. Known as One Times Square (at 1475 Broadway in Midtown Manhattan), it was the headquarters for " The New York Times, " which gave Times Square its name. Completed in 1905, it reached a height of to its roof, or including its rooftop flagpole, which the " Times " vainly hoped would give it a record high status. But because a flagpole is not an integral architectural part of a building, One Times Square was not generally considered to be taller than the Park Row Building in Lower Manhattan, which was therefore still New York's tallest.

A bigger controversy was the rivalry between two New York skyscrapers built in the Roaring Twenties — the Chrysler Building and the Bank of Manhattan Trust Building, now called the Trump Building but better known as 40 Wall Street (thus avoiding confusion with the many other Trump-named buildings). The latter was tall, had a shorter pinnacle, and had a much higher top occupied floor (the second category in the 1996 criteria for tallest building). In contrast, the Chrysler Building employed a very long spire secretly assembled inside the building to claim the title of world's tallest building with a total height of, despite having a lower top occupied floor and a shorter height when both buildings' spires are not counted in their heights. Although the architects of record for 40 Wall were H. Craig Severance and Yasuo Matsui, the firm of Shreve & Lamb (who also designed the Empire State Building) served as consulting architects. They wrote a newspaper article claiming that 40 Wall was actually the tallest, since it contained the world's highest usable floor. They pointed out that the observation deck of 40 Wall was nearly higher than the top floor of the Chrysler, whose surpassing spire was strictly ornamental and essentially inaccessible. Despite the protest, the Chrysler Building was generally accepted as the tallest building in the world for almost a year, until it was surpassed by the Empire State Building’s in 1931.

That was in turn surpassed by the twin towers of New York’s original World Trade Center in 1972, which were in turn surpassed by the Sears Tower in Chicago in 1974. Now called the Willis Tower (since 2009) it was to its flat rooftop, or including its original antennas. But in 1978 One World Trade Center (commonly known as the north tower) attained a taller absolute height when it added its new broadcasting antenna, for a total height of. The WTC north tower maintained this height record (including its antenna) from 1978 until 2000, when the owners of the Willis Tower extended its broadcasting antennae for a total height of. Thus the status of the Willis Tower as the “totally” tallest was restored in the face of a new threat looming in the Far East — the “Siamese Twins.”

A major controversy erupted upon completion of the Petronas Towers in Kuala Lumpur, Malaysia in 1998. These twin towers, at, had a higher architectural height (spires, not antennas), but a lower absolute pinnacle height and a lower top occupied floor than the Willis Tower in Chicago. Counting buildings as structures with floors throughout, and with antenna masts excluded, the Willis was still considered the tallest at that time. Excluding their spires, which are higher than the flat roof of Willis, the Petronas Towers are not taller than Willis. At their convention in Chicago, the Council on Tall Buildings and Urban Habitat (CTBUH) found the Willis Tower (without its antennas) to be the third-tallest building, and the Petronas Towers (with their spires) to be the world's two tallest buildings.

Responding to the ensuing controversy, the CTBUH then revised their criteria and defined four categories in which the world's tallest building can be measured, retaining the old criterion of height to architectural top, and adding three new categories:The height-to-roof criterion was discontinued because relatively few modern tall buildings possess flat rooftops, making this criterion difficult to determine and measure. The CTBUH has further clarified their definitions of building height, including specific criteria concerning subbasements and ground level entrances (height measured from lowest, significant, open-air, pedestrian entrance rather than from a previously undefined "main entrance"), building completion (must be topped out both structurally and architecturally, fully clad, "and" able to be occupied), condition of the highest occupied floor (must be continuously used by people living or working and be conditioned, thus including observation decks, but not mechanical floors) and other aspects of tall buildings.

The height is measured from the level of the lowest, significant, open-air, pedestrian entrance. At the time, the Willis Tower held first place in the second and third categories, the Petronas Towers held the first category, and the original WTC north tower held the fourth (height to tip) category with its antenna. In 2000, however, a new antenna mast was placed on the Willis Tower, giving it the record in the fourth category. On April 20, 2004, the 101-storey Taipei 101 in Taipei, Taiwan, was completed, taking the world record for the first three categories. On July 21, 2007, it was announced that Burj Khalifa in Dubai, UAE, had surpassed Taipei 101. Since its completion in early 2010, Burj Khalifa leads in all categories (the first building to do so) with its spire height of.

Before Burj Khalifa was completed, Willis Tower led in the height-to-tip category with after its antenna was extended in 2000, making Willis Tower slightly taller height-to-tip than the WTC north tower's antenna that measured. After the September 11, 2001, attacks, the WTC became the world's tallest two buildings to be destroyed or demolished. They took that distinction from the Singer Building, which stood tall until the late 1960s where One Liberty Plaza now stands right across Church Street from the WTC site.

A different superlative for skyscrapers is their number of floors. The original World Trade Center set that record at 110 in the early 1970s, and this was not surpassed until the Burj Khalifa opened in 2010.

Structures such as the CN Tower, the Ostankino Tower and the Oriental Pearl Tower are excluded from these categories because they are not "habitable buildings", which are defined as frame structures made with floors and walls throughout.

Freestanding structures must not be supported by guy wires, the sea or other types of support. It therefore does not include guyed masts, partially guyed towers and drilling platforms but does include towers, skyscrapers (pinnacle height) and chimneys.
"(See also history of tallest skyscrapers.)"

The world's tallest freestanding structure on land is defined as the tallest self-supporting artificial structure that stands above ground. This definition is different from that of world's tallest building or world's tallest structure based on the percentage of the structure that is occupied and whether or not it is self-supporting or supported by exterior cables. Likewise, this definition does not count structures that are built underground or on the seabed, such as the Petronius Platform in the Gulf of Mexico. Visit world's tallest structure by category for a list of various other definitions.

The tallest freestanding structure on land is the Burj Khalifa in Dubai, United Arab Emirates. The building surpassed the height of the previous record holder, the CN Tower in Toronto, Ontario, on September 12, 2007. It was completed in 2010, with final height of.

The following is a list of structures that have held the title as the tallest freestanding structure on land.

Notable mentions include the Pharos (lighthouse) of Alexandria, built in the third century BC and estimated between. It was the world's tallest non-pyramidal structure for many centuries. Another notable mention includes the Jetavanaramaya stupa in Anuradhapura, Sri Lanka, which was built in the third century, and was similarly tall at. These were both the world's tallest or second-tallest non-pyramidal structure for over a thousand years.

The tallest "secular" building between the collapse of the Pharos and the erection of the Washington Monument may have been the Torre del Mangia in Siena, which is tall, and was constructed in the first half of the fourteenth century, and the Torre degli Asinelli in Bologna, also Italy, built between 1109 and 1119.

Timeline of development of world's highest observation deck since inauguration of Eiffel Tower.

Higher observation decks have existed on mountain tops or cliffs, rather than on tall structures. The Grand Canyon Skywalk, constructed in 2007, protrudes over the west rim of the Grand Canyon and is approximately above the Colorado River, making it the highest of these types of structures.

As most of the tallest structures are guyed masts, here is a timeline of world's tallest guyed masts, since the beginning of radio technology.

As many large guyed masts were destroyed at the end of World War II, the dates for the years between 1945 and 1950 may be incorrect. If Wusung Radio Tower survived World War II, it was the tallest guyed structure shortly after World War II.

Towers include observation towers, monuments and other structures not generally considered to be "habitable buildings", they are meant for "regular access by humans, but not for living in or office work, and are self-supporting or freestanding, which means no guy-wires for support", meaning it excludes from this list of continuously habitable buildings and skyscrapers as well as radio and TV masts.

Bridge towers or pylons, chimneys, transmission towers, and most large statues allow human access for maintenance, but not as part of their normal operation, and are therefore not considered to be towers.

The Tokyo Skytree, completed in February 2012, is, making it the tallest tower, and second-tallest freestanding structure in the world.

The following is a list of structures that have historically held the title as the tallest towers in the world.
The list categories are:

Notes:

Source: Emporis

The Council on Tall Buildings and Urban Habitat, an organization that certifies buildings as the "World's Tallest", recognizes a building only if at least 50% of its height is made up of floor plates containing habitable floor area. Structures that do not meet this criterion, such as the CN Tower, are defined as "towers".

There are dozens of radio and television broadcasting towers which measure over 600 metres (about 2,000 ft) in height, and only the tallest are recorded in publicly available information sources.

Within an accepted definition of a building further controversy has included the following factors:

This category does not require the structure to be "officially" open but does require it to be "topped out".

Burj Khalifa broke the height record in all four categories for completed buildings.

"Note:" The following table is a list of the tallest completed structure in each of the structural categories below. For a list of structures by function see the list later in the article. There can only be one structure in each category, unless the tallest is the same for more than one structure in the same category.

There are some destroyed architectural structures which were taller than the tallest existing structure of their type. There are also destroyed structures omitted from this list that had been surpassed in height prior to being destroyed.

* "Mixed-use" is defined as having three or more real estate uses (such as retail, office, hotel, etc.) that are physically and functionally integrated in a single property and are mutually supporting.

A different superlative for skyscrapers is their number of floors. The original World Trade Center set that record at 110 in the early 1970s, and this was not surpassed until the Burj Khalifa opened in 2010.

Structures such as the CN Tower, the Ostankino Tower and the Oriental Pearl Tower are excluded from these categories because they are not "habitable buildings", which are defined as frame structures made with floors and walls throughout.

Freestanding structures must not be supported by guy wires, the sea or other types of support. It therefore does not include guyed masts, partially guyed towers and drilling platforms but does include towers, skyscrapers (pinnacle height) and chimneys.
"(See also history of tallest skyscrapers.)"

The tallest freestanding structure on land is the Burj Khalifa in Dubai, United Arab Emirates. The building surpassed the height of the previous record holder, the CN Tower in Toronto, Ontario, on September 12, 2007. It was completed in 2010, with final height of.

The following is a list of structures that have held the title as the tallest freestanding structure on land.

The tallest "secular" building between the collapse of the Pharos and the erection of the Washington Monument may have been the Torre del Mangia in Siena, which is tall, and was constructed in the first half of the fourteenth century, and the Torre degli Asinelli in Bologna, also Italy, built between 1109 and 1119.

Timeline of development of world's highest observation deck since inauguration of Eiffel Tower.

Higher observation decks have existed on mountain tops or cliffs, rather than on tall structures. The Grand Canyon Skywalk, constructed in 2007, protrudes over the west rim of the Grand Canyon and is approximately above the Colorado River, making it the highest of these types of structures.

As most of the tallest structures are guyed masts, here is a timeline of world's tallest guyed masts, since the beginning of radio technology.

As many large guyed masts were destroyed at the end of World War II, the dates for the years between 1945 and 1950 may be incorrect. If Wusung Radio Tower survived World War II, it was the tallest guyed structure shortly after World War II.

Bridge towers or pylons, chimneys, transmission towers, and most large statues allow human access for maintenance, but not as part of their normal operation, and are therefore not considered to be towers.

The Tokyo Skytree, completed in February 2012, is, making it the tallest tower, and second-tallest freestanding structure in the world.

The following is a list of structures that have historically held the title as the tallest towers in the world.
The list categories are:

Notes:

Source: Emporis


When was William O'Brien born?

William O'Brien was probably born in County Clare in about 1740 to a family which claimed a distant connection to the Viscounts Clare. His father was a fencing master in Dublin David Garrick brought O'Brien over to London from Dublin in 1758 to join his actor's company at Drury Lane. O'Brien was successful in a number of roles, particularly Shakespeare and contemporary comedies. O'Brien was an actor in the company of He eloped with Lady Susannah "Susan" Fox-Strangways, eldest daughter of Stephen Fox, the first Earl of Ilchester, whom he had met when they both performed in amateur theatricals at Holland House. Their marriage, which took place on 7 April 1764 at St. Paul's Church, Covent Gardens, was disapproved of by Lady Susan's family.

William O'Brien (actor)

William O'Brien (c.1740-1815) was an Irish actor and playwright.

Following the marriage, O'Brien retired from the stage. The couple were forced for a time to travel to North America, because of the social scandal caused by their elopement. They set sail for New York in September 1764. Although neither husband nor wife were happy there, they travelled widely, sailing up the Hudson, travelling west to Niagara Falls, and then north to Quebec where O'Brien briefly served as a barrack master. In 1768, he was gazetted Secretary and Provost-Master-General of the Bermudas.

On their return to England in 1770, the O'Briens lived for a time in London where O'Brien entered a brief but unsuccessful career as a playwright. He was the author of two plays, "Cross-Purposes" (1772) and "The Duel" (1773). The diarist James Boswell described O'Brien as "a lively little fellow, but priggish" and "quite the fine man about town".

The O'Briens later moved to live at a Strangways family property, Stinsford House, in Dorset. The couple had no children. O'Brien served as Receiver-General of Dorset until shortly before his death in 1815. O'Brien and Lady Susan were buried together at the church of St Michael's at Stinsford.

Nicholas Irons portrayed O'Brien in the 1999 TV miniseries "Aristocrats".

William O'Brien (born 26 January 1929) is an English former footballer who played in the Football League for Darlington. A centre half born in Middlesbrough, O'Brien began his football career as a junior with his hometown club, Middlesbrough F.C., and was on the books of Leicester City for the 1947–48 season before serving in the Army. He joined Darlington in February 1950, but did not make his first-team debut for more than a year, when he replaced the injured Geoff Stone on 17 March 1951 for a 4–1 defeat at home to Bradford City. He kept his place for the next Third Division North matchan even heavier defeat, this time away to Hartlepools Unitedbut that was his final appearance.

Willie O'Brien

James O'Brien was the son of William O'Brien, 3rd Earl of Inchiquin, and his wife, Mary Villiers, daughter of Sir Edward Villiers. He was born in 1701 at Inchiquin, County Clare. Not long after his birth, his family relocated to Charleville, County Cork. He married Mary Jephson, the daughter of the Very Reverend William Jephson, Dean of Kilmore, and Anne Barry.

James O'Brien (1695–1771)

Hon. James O'Brien (1701 – 18 December 1771) was an Irish nobleman and politician.

From 1725 to 1727, O'Brien sat as a Member of the Irish House of Commons for Charleville. In 1727, he was elected to the Irish House of Commons for Youghal. He held this seat until his retirement in 1761. While serving in Parliament, O'Brien and his family lived in Drogheda, where he held the position of Collector of Customs for the Port of Drogheda. He retired to his brother's estate at Rostellan, County Cork. During his residency there, O'Brien served as Collector of Customs for the Port of Cork until 1767. He died at Rostellan Estate in 1771.

O'Brien also served time as Grand Master of the Freemasons of Munster. He was unanimously elected in 1727. In the army, he held the rank of Captain of Foot.

Children of James O'Brien and Mary Jephson:

William O'Brien (2 October 1852 – 25 February 1928) was an Irish nationalist, journalist, agrarian agitator, social revolutionary, politician, party leader, newspaper publisher, author and Member of Parliament (MP) in the House of Commons of the United Kingdom of Great Britain and Ireland. He was particularly associated with the campaigns for land reform in Ireland during the late 19th and early 20th centuries as well as his conciliatory approach to attaining Irish Home Rule.

William O'Brien

William O'Brien was born at Bank Place in Mallow, County Cork, as second son of James O'Brien, a solicitor's clerk, and his wife Kate, the daughter of James Nagle, a local shopkeeper. On his mother's side he was descended from the distinguished Norman family of Nagles, long settled in the vicinity of Mallow giving their name to the nearby Nagle Mountains. He was also linked through his mother with the statesman Edmund Burke's mother's family, as well as with the poet Edmund Spencer's family.
The Nagles however, no longer held the status or prosperity they once had. In the same month thirty-eight years earlier Thomas Davis was born in Mallow. O'Brien's advocacy of the cause of Irish Independence was to be in the same true tradition of his esteemed fellow-townsman. Following in his footsteps he acknowledged the existence of many strands of Irishness.

O'Brien shared his primary education with a townsman with whom he was later to have a close political connection, Canon Sheehan of Doneraile. He enjoyed his secondary education at the Cloyne diocesan college, which resulted in his being brought up in an environment noted for its religious tolerance. He greatly valued having had this experience from an early age, which strongly influenced his later views for the need of such tolerance in Irish national life.

Financial misfortune in 1868 caused the O'Brien family to move to Cork City. A year later his father died, and the illness of his elder and younger brother and his sister resulted in him having to support his mother and siblings. Always a prolific writer, it quickly earned him a job as newspaper reporter, first for the "Cork Daily Herald". This was to be the primary career which first attracted attention to him as a public figure. He had begun legal studies at Queen's College, later University College Cork, but although he never graduated, he held a lifelong attachment to the institution, to which he bequeathed his private papers.

From an early age O'Brien's political ideas, like most of his contemporaries, were shaped by the Fenian movement and the plight of the Irish tenant farmers, his elder brother having participated in the rebellion of 1867. It resulted in O'Brien himself becoming actively involved with the Fenian brotherhood, resigning in the mid-1870s, because of what he described in 'Evening Memories' (p. 443–4) as "the gloom of inevitable failure and horrible punishment inseparable from any attempt at separation by force of arms".

As a journalist his attention was attracted in the first place to the suffering of the tenant farmers. Now on the staff of the "Freeman's Journal", after touring the Galtee Mountains around Christmas 1877 he published articles describing their conditions, which later appeared in pamphlet form. With this action he first displayed his belief that only through parliamentary reform and with the new power of the press that public opinion could be influenced to pursue Irish issues constitutionally through open political activity and the ballot box. Not least of all, responding to the hopes of the new Irish Home Rule movement.

In 1878 he met Charles Stewart Parnell MP at a Home Rule meeting. Parnell recognised his exceptional talents as a journalist and writer, influencing his rise to becoming a leading politician of the new generation. He subsequently appointed him in 1881 as editor of the Irish National Land League's journal, "United Ireland". His association with Parnell and the Irish Parliamentary Party (IPP) led to his arrest and imprisonment with Parnell, Dillon, William Redmond and other nationalist leaders in Kilmainham Gaol that October.

During his imprisonment until April 1882 he drafted the famous Land War "No Rent Manifesto" – a rent-withholding scheme personally led by O'Brien, escalating the conflict between the Land League and Gladstone's government.

From 1883–1885 O'Brien was elected MP for Mallow. Following the abolition of that constituency he represented Tyrone South from 1885 to 1886, North East Cork from 1887–1892, and Cork City from 1892–1895 and from 1901–1918, in the House of Commons. There were three periods of absence: 1886-7, from 1895–1900, and eight months in 1904. Amid the turmoil of Irish politics in the late 19th century he was frequently arrested and imprisoned for his support for various Land League protests.

In 1884, through the newspaper "United Ireland" he incited a sensational homosexual scandal involving officers at Dublin Castle.

In 1887 O'Brien helped to organise a rent strike during the Plan of Campaign at the estate of Lady Kingston near Mitchelstown, County Cork. On 9 September, after an 8,000-strong demonstration led by John Dillon MP, three estate tenants were shot dead, and others wounded, by police at the town's courthouse where O'Brien had been brought for trial on charges of incitement under a new Coercion Act. This event became known as the Mitchelstown Massacre. Later that year, thousands of demonstrators marched in London to demand his release from prison, and clashed with police at Trafalgar Square on Bloody Sunday (13 November).
Even in prison, O'Brien continued his protests, refusing to wear prison uniform in 1887. Being left without clothes, a Blarney tweed suit was smuggled in. He occasionally wore this much publicised suit in the Commons when confronting his incarcerator, Arthur Balfour. His imprisonment also inspired protests – notably the 1887 'Bloody Sunday' riots in London. In 1889 he escaped from a courtroom but was sentenced "in absentia" for conspiracy. He fled to America accompanied by Dillon who was on bail, then to France where both held negotiations with Parnell at Boulogne-sur-Mer over the leadership of the party. When these broke down, both returned to Folkestone giving themselves up, subsequently serving four months in Clonmel and Galway gaols. Here O'Brien began to reconsider his political future, having already been prosecuted nine times over years, using the time to write an acclaimed novel, a Fenian romance with a land reform theme set in 1860: "When We Were Boys", which was published in 1890.

In 1890 he married Sophie Raffalovich, sister of the poet Marc André Sebastian Raffalovich and the economist Arthur Raffalovich, and daughter of the Russian Jewish banker, Hermann Raffalowich, domiciled in Paris. It was to mark a major turning point in O'Brien's personal and political life. His wife brought considerable wealth into the marriage, enabling him to act with political independence and providing finances to establish his own newspapers. His wife (1860–1960) who survived him by over 30 years, gave him considerable moral and emotional support for his political pursuits. Their relationship added an abiding love for France and attachment to Europe to his life, where he often retired to recuperate.

By 1891 he had become disillusioned with Parnell's political leadership, although emotionally loyal to him he tried to persuade him to retire after the O'Shea divorce case. On Parnell's death that year and the ensuing IPP split, he remained aloof from aligning himself with either side of the Party, either the rump pro-Parnellite Irish National League (INL) led by John Redmond MP or with the anti-Parnellite Irish National Federation (INF) group under John Dillon, although he saw the weight of strength in the latter. O'Brien worked hard in the 1893 negotiations leading to the Commons passing Gladstone's Second Home Rule Bill, which the Lords however rejected. ( on the First Home Rule Bill had beseeched parliament not to reject it).

Distancing himself from the party turmoils, he retired from parliament in 1895, settling for a while with his wife near Westport, County Mayo, which enabled him to experience at first hand from his Mayo retreat the distressed hardship of the peasantry in the West of Ireland, trying to eke out an existence in its rocky landscape.

Believing strongly that agitational politics combined with constitutional pressures were the best means of achieving objectives, O'Brien established on the 16. January 1898 the United Irish League (UIL) at Westport, with Michael Davitt as co-founder and John Dillon present. It was to be a new grass-roots organisation with a programme to include agrarian agitation, political reform and Home Rule. It coincided with the passing of the revolutionary Local Government (Ireland) Act 1898 which broke the power of the landlord dominated "Grand Juries", passing for the first time absolute democratic control of local affairs into the hands of the people through elected Local County Councils.

The UIL was explicitly designed to reconcile the various parliamentary fragments existing since the Parnell split, which proved very popular, its branches sweeping over most of the country organised by its general secretary John O'Donnell, dictating to the demoralised Irish party leaders the terms for reconstruction, not only of the party but the nationalist movement in Ireland. The movement was backed by O'Brien's new newspaper "The Irish People".

Around 1900 O'Brien, an unbending social reformer and agrarian agitator, was the most influential and powerful figure within the nationalist movement, although not formally its leader. His UIL was by far the largest organisation in the country, comprising 1150 branches and 84,355 members. The result of the rapid growth of his UIL as a national organisation in achieving unity through organised popular opinion, was to effect a quick defensive reunion of the discredited IPP factions of the INL and the INF, largely fearing O’Brien's return to the political field. He can nevertheless be regarded as the architect of the settlement of 1900. The unity under John Redmond disturbed O’Brien, as it resulted in most of the ineffective party candidates being re-elected in the 1900 general election, preventing the UIL from using its power in the pre-selection of candidates. Within a few years the IPP was however, to tactically adjunct the UIL under its wing manoeuvering it out of O'Brien's control.

O'Brien next intensified the UIL agitation for land purchase by tenant farmers, pressurising for compulsory purchase. He formed an alliance with constructive unionists which resulted in the calling of the December 1902 Land Conference, an initiative by moderate landlords led by Lord Dunraven for a settlement by conciliatory agreement between landlord and tenant. The tenant representation was led by O'Brien, the others were John Redmond, Timothy Harrington and T. W. Russell for the Ulster tenants. After six sittings all eight tenant's demands were conceded (one with compromise), O’Brien having guided the official nationalist movement into endorsement of a new policy of "conference plus business". He followed this by campaigning vigorously for the greatest piece of social legislation Ireland had yet seen, orchestrating the Wyndham "Land Purchase Act (1903)" through parliament, which effectively ended landlordism, solving the age old Irish Land Question.

This masterful strategy of bringing about agreement on land purchase between tenants and landlords under the Act, resulted in a rush of landlords to sell and of tenants to buy. Though the Act was approved by Redmond, his deputy Dillon disfavoured the Act because he opposed any co-operation with landlords and Michael Davitt objected to peasant proprietorship under the Act, demanding land nationalisation. Together with Thomas Sexton editor of the party's "Freeman's Journal", all three campaigned against O’Brien, fiercely attacking him for putting Land Purchase and Conciliation before Home Rule. O'Brien appealed to Redmond to suppress their opposition but it went unheeded. Declaring that he was making no headway with his policy, he resigned his parliamentary seat in November 1903, closed down his paper the "Irish People" and left the party for the next five years. It was a serious setback for the party. It also turned once intimate friends into mortal enemies. His Cork electorate however, insisted on pushing through his re-election eight months later in August 1904. O’Brien had failed in his intention of shocking the party to its senses.

During 1904 O'Brien had already embarked on advancing full scale implementation of the Act in alliance with D. D. Sheehan MP and his Irish Land and Labour Association (ILLA), when they formed the Cork Advisory Committee to help tenants in their negotiations. Their collaboration became the new organisational base for O'Brien's political activities. This new alliance aggravated the Dillonite section of the IPP further. Determined to destroy both of them "before they poison the whole country", Dillon and the party published regular denunciations in the "Freeman's Journal", then coupéd O'Brien's UIL with the appointment of its new secretary, Dillon's chief lieutenant, Joseph Devlin MP, Grandmaster of the Ancient Order of Hibernians, Devlin eventually gaining organisational control over the entire UIL and IPP organisations.

O'Brien had in the mean time engaged with the Irish Reform Association, together with Sir Anthony MacDonnell, a Mayo Catholic originally appointed by Wyndham, and head of the Civil Service in Dublin Castle, anxious to do something for Ireland. MacDonnell helped the reform group to draft a scheme on the possible extension of the principle of self-government for Ireland. On 31 August 1904 the Reform Association released a preliminary report calling for the devolution of larger powers of local government for Ireland. The limited scheme was quickly and equally condemned by O'Brien's opponents, who regarded it nevertheless as a step in the right direction.

Britain had two bills to pay for past wrongs. After financing tenant land purchase, tenant farmers were now proud proprietors largely in control of local government. The next bill to pay was for extensive rural housing of the tens of thousands of migrant farm labourers struggling to survive in stone cabins, barns or mud hovels. This was a long-standing demand by the ILLA branches and D.D. Sheehan. In 1904 O'Brien then joined forces with Sheehan's ILLA organisation, identifying himself with labourer's grievances and Sheehan's demand for agricultural labourers' housing, who up to then were dependent on limited provision of cottages by local County Councils or landowners at unfavourable terms.

Following demonstrations of amazing extent addressed by O’Brien and his friends during 1904 which fought and won the field in Charleville and Macroom (counties Cork), Kilfinane and Dromcolliher (counties Limerick), Tralee and Castleisland (counties Kerry), Scariff co. Clare, Goolds Cross co. Tipperary and Ballycullane co. Wexford, a breakthrough occurred when a scheme was made public at ""the largest labour demonstration ever held in Ireland"" ("Cork Examiner"), a memorable rally in Macroom on Sunday 11 December 1904 addressed by William O'Brien. Preaching a gospel of social justice, his concepts became known as the `Macroom programme´. O'Brien grasped the prime importance of its principles and measures, when during 1905 he pressed and negotiated together with support from Sir Anthony MacDonnell (the Under-Secretary for Ireland) for what was subsequently carried into law and after the January 1906 general election became the unprecedented Bryce "Labourers (Ireland) Act (1906)".

The Second Phase of the Labourers Acts (1906–1914) began after the 1906 Labourers Housing Act, long demanded by the ILLA, was implemented, for which both the Redmondite and O'Brienite factions were zealous in claiming credit. The labourer-owned cottages erected by the Local County Councils brought about a major socio-economic transformation, by simultaneously erasing the previous inhuman habitations. O'Brien saying that the Labourers Acts – "were scarcely less wonderworking than the abolition of landlordism itself". In 1904 Davitt going so far as to declare the foreseen Labourers Act constituted – "a rational principle of state Socialism". This Act had enormous positive long-term consequences for rural Irish society.

The so called 'Labourers Act' provided large scale funding for extensive state sponsored housing to accommodate rural labourers and others of the working classes. The programme financed and produced during the course of the next five years, the erection of over 40,000 working-class cottages, each on an acre of land, a complete'municipalisation' of commodious dwellings dotting the rural Irish countryside. This unique social housing programme unparalleled anywhere else in Europe brought about an unsurpassed agrarian revolution, changing the face of the Irish landscape, much to O'Brien's expressed delight.
Renewed publication of O'Brien's newspaper "The Irish People" (1905–1909) exalting the cottage building, its editorials equally countermanding the IPPs' "Dublin bosses" attempts to curtail the programme, fearing settled rural communities would no longer be dependent on Party and Church. Munster took full advantage, erecting most of the cottages, additional funding providing for a further 5,000 houses under Birrell's. The bulk of the labourers' cottages were erected by 1916, resulting in a widespread decline of rampant tuberculosis, typhoid and scarlet fever.

In the interest of political unity, O'Brien and other excluded MPs temporarily rejoined the Parliamentary Party when Redmond summoned a unity meeting in the Mansion House, Dublin in April 1908. Later that year, during negotiations for additional funding of land purchase under an amending bill, Redmond called a further UIL National Convention for 9 February 1909 in Dublin to regulate the issues, claiming the bill over-burdened the British Treasury and the rate payers. Over 3000 delegates attended. Devlin had the hall filled in advance with forces of his "militant Mollies", so that when O'Brien and his followers tried to speak in favour of the bill, they were battoned into silence. The convention then dubbed the 'Baton' Convention by O'Brien. It was ""probably the stormiest meeting ever held by constitutional nationalists"".

The bill eventually passed into law as Birrell's "Land Purchase Act (1909)", but falling far short in its financial provisions.

As an outcome of the "Baton Convention" O’Brien felt himself again driven from the party. He foresaw that the IPP, undermined by the AOH, was on a fatal radical path which would frustrate any All-Ireland Home Rule settlement. As a counter measure he set about establishing a new League, which was to build on the success his combined "doctrine of conciliation" with "conference plus business" achieved during the 1902 Land Conference with landlords and the ensuing 1903 Land Purchase Act. Following his engagement with the Irish Reform Movement 1904-5 and support of the 1907 Irish Council Bill which he viewed as a step in the right direction, or "Home Rule by instalments", he firmly believed all moderate unionists could still be won over to All-Ireland Home Rule. For many nationalists on the other hand, the adoption of a conciliatory approach to the "hereditary enemy" involved too sharp a deviation from traditional thinking.

In March 1909 he inaugurated the All-for-Ireland League (AFIL) in Kanturk with James Gilhooly MP as Chairman and D. D. Sheehan Hon. Secretary. The AFIL's political objective was the attainment of an All-Ireland parliament with the consent rather than by the compulsion of the Protestant and Unionist community, under the banner of the "Three Cs", for Conference, Conciliation and Consent as applied to Irish politics. The League was supported by many prominent Protestant gentry, leading landlords and Munster business figures. The political activist Canon Sheehan of Doneraile was also a founder member and wrote in a very long editorial for the first issue of the League's new newspaper its political manifesto.

Ill-health striking O’Brien, he departed for Florence, Italy to recuperate, returning for the January 1910 general election, in which the Cork electorate returned eight "O'Brienite" MPs. Throughout 1910 his AFIL movement opposed an Irish Party supported by the Catholic clergy. It returned eight independent AFIL MPs in the December 1910 general election to be O'Brien's new political party. From July 1910 until late 1916 O’Brien published the League's newspaper, the "Cork Free Press". Election results published by it showed Independents throughout Ireland had won 30% of votes cast.

O’Brien saw it opportune for a co-operative understanding with Arthur Griffith's moderate Sinn Féin movement, having in common – attaining objectives through "moral protest" – political resistance and agitation rather than militant physical-force. Neither O’Brien nor Griffith advocated total abstentionism from the Commons, and regarded Dominion Home Rule, modelled on Canada or Australia, as acceptable. Although Griffith favoured co-operation, a special Sinn Feín executive council meeting called to consider co-operation regretted it was not possible because its constitution would not allow it. In the following years O’Brien and his party continued to associate themselves with Griffith's movement both in and out of parliament. In June 1918 Griffith asked O’Brien to have the writ moved for his candidacy in the Cavan-east by-election (moved by AFIL MP Eugene Crean) to which Griffith was elected with a sizeable majority.

On 2 November 1911 O'Brien proposed full Dominion status similar to that enjoyed by Canada, in an exchange of views with Asquith, as the only viable solution to the "Irish Question". Home Rule became technically assured after a new Home Rule bill was introduced in 1912 with the IPP holding the balance of power at Westminster. During the 1913–14 parliamentary debates on the Third Home Rule Bill, O'Brien, alarmed by Unionist resistance to the bill, opposed the IPP's coercive "Ulster must follow" policy, and published in the "Cork Free Press" end of January 1914 specific concession, including a suspensory veto right, which would enable Ulster join a Dublin Parliament "any price for an United Ireland, but never partition". William O'Brien resigned his seat as MP again for a fourth time in January and re-stood to test local support for his policies, after the All-for-Ireland League suffered heavy defeats in the Cork City municipal elections.

After the opening of parliament in February 1914 the threat of rebellion in Ulster gave O'Brien the opportunity to make an eloquent speech on the 24 February calling for generous concessions towards Ulster, but warning he would'strenuously oppose exclusion'. When the Ulster Volunteers armed in April to resist likely "Rome Rule", Redmond's Irish Volunteers armed likewise to ensure enactment of all-Ireland self-government. During the final stages of the second reading and debate on the Third Home Rule Bill in the House of Commons, which was accompanied by Asquith's guarantee that it would never be enforced without an Amending Bill enacting the exclusion of the six Ulster counties with a Protestant majority, O'Brien made a powerful lengthy speech on 1 April 1914 reiterating at length his proposals to enable Ulster remain within an All-Ireland settlement, by means of a suspensory veto upon any bill passed by a Dublin Parliament, amongst other rights and protections. Stating "I condemn and abhor with all my heart the preparations of the Ulster Volunteers for even the possibility of slaughter between Irishmen and Irishmen". Otherwise Ireland once divided would remain divided and 'the line on which you are presently travelling will never bring you anything except division and disaster'.

Opposing O'Brien's proposals and initiatives, the Redmond-Dillon-Devlin (IPP-UIL-AOH) hardline alliance remained uncompromising with their standpoint – "no concessions for Ulster". In the Commons on 25 May O'Brien stated that "we are ready for almost any conceivable concession to Ulster that will have the effect of uniting Ireland, but we will struggle to our last breath against a proposal which will divide her, and divide her eternally, if Ireland's own representatives are once consenting parties..." after which he and his followers holding true to their pledge, abstained from the final vote passing the Home Rule Act 1914, denouncing the bill as a "ghastly farce" ultimately as a "partition deal" after Sir Edward Carson leader of the Ulster Unionist Party forced through an amendment mandating the partition of Ireland, the Irish Nationalists' confrontation course with Ulster ending in fiasco.

With the outbreak of World War I on 4 August 1914, Asquith proposed a Suspensory Bill for the Home Rule Bill. It received Royal Assent simultaneously with its counterpart, the Government of Ireland Act 1914, on the 18 September. Although the two controversial Bills had now finally reached the statute books, the Suspensory Act ensured that Home Rule would be postponed for the duration of the conflict. In the debate on 15 September in the House of Commons concerning the Suspensory Bill, O'Brien made it again clear ""that while we are prepared to pay almost any other price for a general national settlement, there is one price which some of us, at all events, will never in any possible circumstances consent to pay, and that is the dismemberment of our ancient Irish nation"". He concluded by turning to 'our fellow countrymen in Ulster' in proposing to secure for them a position of undiminished citizenship in this Empire under some projected scheme of federalism.

O'Brien saw the outbreak of World War I in August as an opportunity to undertake a last crusade to preserve at any price the unity of Ireland, by uniting the Green and Orange in a common cause, declaring himself on the side of the Allied and Britain's European war effort. O'Brien was the first Nationalist leader to call on Irish Volunteers for the front. Towards the end of August he had an interview with Lord Kitchener, Secretary of State for War, and laid before him a scheme for raising an Irish Army Corps embracing all classes and creeds, South and North. Kitchener (incidentally a Protestant and born in County Kerry) favoured the idea. O’Brien immediately summoned a meeting held in the Cork Town Hall under the auspices of the All-for-Ireland League on 2 September, the hall packed with an enthusiastic audience of men and women. In a speech that far exceeded Redmond's in favour of its adherence to England cause, he said:- :

O'Brien later wrote: "Whether Home Rule is to have a future will depend upon the extent to which the Nationalists in combination with Ulster Covenanters, do their part in the firing line on the fields of France". He stood on recruiting platforms with the other National leaders and spoke out encouragingly in favour of voluntary enlistment in the Royal Munster Fusiliers and other Irish regiments.

O'Brien, alarmed at the increased activity of Sinn Féin in 1915, predicted the danger of a potential republican eruption, culminating in the IRB 1916 Rebellion, in which however Sinn Féin were not involved. He was forced to cease publication of his "Cork Free Press" in 1916 soon after the appointment of Lord Decies as Chief Press Censor for Ireland. Decies warned the press to be careful about what they published. Such warnings had little effect when dealing with such papers as the "Cork Free Press". It was suppressed after its republican editor, Frank Gallagher, accused the British authorities of lying about the conditions and situation of republican prisoners in the Frongoch internment camp.
O'Brien accepted the Rising and the ensuing changed political climate in 1917 as the best way of ridding the country of IPP and AOH stagnation. Home Rule had been lost in 1913, an inflexible IPP long out of touch with reality, reflected by Britain's two failed attempts to introduce Home Rule in 1916 and again in 1917. O'Brien refused to participate in the Irish Convention after southern unionist representatives he had proposed were turned down. The Convention ended as he predicted in failure when Britain attempted to link the enactment of Home Rule with conscription.

During the anti-conscription crisis in April 1918 O'Brien and his AFIL left the House of Commons and joined Sinn Féin and other prominentaries in the mass protests in Dublin. Seeing no future for his conciliatory political concepts in a future election, he believed Sinn Féin in its moderate form had earned the right to represent nationalist interests. He and the other members of his All-for-Ireland League party stood aside putting their seats at the disposal of Sinn Féin, its candidates returned unopposed in the December 1918 general elections. In an address to the election he had said: ""We cannot subscribe to a programme of armed resistance in the field, or even of permanent withdrawal from Westminster; but to the spirit of Sinn Féin, as distinct from its abstract programme, the great mass of independent single-minded Irishmen have been won over, and accordingly they ought now to have a full and sympathetic trial for enforcing the Irish nation's right of self-determination.""

O'Brien disagreed with the establishment of a southern Irish Free State under the Treaty, still believing that Partition of Ireland was too high a price to pay for partial independence. He wrote in 1923, "It is now obvious enough that, had the Irish Council Bill been allowed to pass in 1907, the Partition of Ireland would never have been heard of." Retiring from political life, he contented himself with writing and declined Éamon de Valera's offer to stand for Fianna Fáil in the 1927 general election. He died suddenly on 25 February 1928 while on a visit to London with his wife at the age of 75. His remains rest in Mallow, and one of the principal streets in the town bears his name to this day. His head-bust overlooks the town Council's Chamber Room and one of his finest portraits hangs in University College Cork.

In 1920 Arthur Griffith said of O'Brien:" "The task of William O’Brien's generation was well and bravely done, had it not been so the work we are carrying out in this generation would have been impossible. In that great work none of Parnell's lieutenants did so much as William O’Brien." "

O'Brien's books, a number of which are collections of his journalistic writings and political speeches, include: