Title: List of tallest buildings
Content:  Historically, the world's tallest man-made structure was the Great Pyramid of Giza in Egypt, which held the position for over 3,800 years until the construction of Lincoln Cathedral in 1311. The Strasbourg Cathedral in France, completed in 1439, was the world's tallest building until 1874. The first skyscraper was pioneered in Chicago with the 138 ft Home Insurance Building in 1885. The United States would hold the position of the world's tallest building throughout the 20th century until 1998, when the Petronas Towers were completed. Since then, two other buildings have gained the title: Taipei 101 in 2004 and Burj Khalifa in 2010. Since the beginning of the 21st century, the Middle East, China, and Southeast Asia have experienced booms in skyscraper construction.
Title: Willis Tower
Content:  The Willis Tower remains the third tallest building in the Americas (after One World Trade Center and Central Park Tower) and the Western Hemisphere. With a pinnacle height of 1729 ft, it is the third-tallest freestanding structure in the Americas, 86 ft shorter than Toronto's CN Tower. It is the eighth-tallest freestanding structure in the world by pinnacle height. At 1482.6 ft tall, including decorative spires, the Petronas Twin Towers in Kuala Lumpur, Malaysia, controversially claimed to be the tallest building in the world in 1998. In the ensuing controversy, four categories of "tallest building" were created. Of these, Petronas was the tallest in the category of height to the top of architectural elements, meaning spires but not antennas. Taipei 101 in Taiwan claimed the record in three of the four 
Title: List of tallest buildings and structures
Content:  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 1250 ft in 1931. That was in turn surpassed by the 1368 ft 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 1451 ft to its flat rooftop, or 1518 ft including its original antennas. But in 1978 One World Trade Center (commonly known as the north tower) attained a taller absolute height when it 
Title: 2013 in architecture
Content:  – Work begins on a Lego model of Durham Cathedral in England, the beginning of a huge fund-raising effort. ; August 3 – The Shanghai Tower, topping out ceremony is held in Shanghai. The tallest building in China and the second-tallest in the world is expected to be completed in 2015. ; October – The sixth World Architecture Festival is held in Singapore. ; November 12 – The Height Committee of the Chicago-based Council on Tall Buildings and Urban Habitat (CTBUH) makes the controversial announcement that One World Trade Center is the tallest building in the United States at 1,776 feet, declaring that the mast on top of the building is a spire since it is a permanent part of the building's architecture. 
Title: List of tallest buildings and structures
Content:   The world's tallest man-made structure is the 828 m 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. Burj Khalifa was developed by Emaar properties, designed by Skidmore, Owings and Merrill and built by BESIX, Samsung Construction and Arabtec. The second-tallest self-supporting structure and the tallest tower in the world is the Tokyo Skytree. The tallest guyed structure is the KVLY-TV mast. 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.
Title: List of tallest buildings in China
Content:   China has the largest number of tall buildings in the world, surpassing that of the second and third largest, the United States (1000+) and United Arab Emirates (400+), combined. As of early 2017, China has more than 1400 skyscrapers above 150 meters (492 ft) of which 48 are "supertall" (300 meters (984 ft) and above). The tallest tower in China is currently the Shanghai Tower, located in the namesake city at a height of 632 m; it is the second-tallest building in the world. The previous 2 tallest buildings in mainland China have also been in Shanghai. The Chinese economic reform from 1978 onwards lead to a significant improvement in quality of living and economic capital. 32 of the 64 buildings (completed and architecturally topped out) with a minimum height of 350 m worldwide are in China (including Hong Kong).
Title: List of tallest buildings and structures
Content:  is even taller with a total height of 1432 m. 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 509.2 m as measured to its architectural height (spire). The height of its roof 449.2 m and highest occupied floor 439.2 m had been surpassed by the Shanghai World Financial Center with corresponding heights of 487 and 474 m. 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 527 m. Burj Khalifa broke the height record in all four categories for completed buildings.
Title: Burj Khalifa
Content:  tallest building, and level 141 reached. ; 12 August 2007: Surpasses the Sears Tower antenna, which stands 527 m. ; 12 September 2007: At 555.3 m, becomes the world's tallest freestanding structure, surpassing the CN Tower in Toronto, and level 150 reached. ; 7 April 2008: At 629 m, surpasses the KVLY-TV Mast to become the tallest man-made structure, level 160 reached. ; 17 June 2008: Emaar announces that Burj Khalifa's height is over 636 m and that its final height will not be given until it is completed in September 2009. ; 1 September 2008: Height tops 688 m, 
Title: List of tallest buildings in Moscow
Content:  Moscow, the capital and largest city of Russia, is home to 12,719 completed high-rises, 22 of which stand taller than 183 m. The tallest building in the city is the 101-story East Tower of the Federation Tower complex, which rises 374 m in the Moscow International Business Center (MIBC) and was completed in 2016. The Federation Tower was the tallest building in Europe upon its completion, and remained the tallest building until 5 October 2017 when it was surpassed by the Lakhta Center in Saint Petersburg, Russia. The second, third, and fourth-tallest buildings in Moscow are the South Tower of OKO, Neva Towers 2, and the Mercury City Tower, respectively, 
Title: Council on Tall Buildings and Urban Habitat
Content:  until completion. The CTBUH also produces an annual list of the ten tallest buildings completed in that particular year. Topping the 2008 list was the 492 m Shanghai World Financial Center in Shanghai, the then tallest building in the world according to the criteria of highest occupied floor, and home to the world's highest observation deck. Second on the 2008 list was the 363 m Almas Tower in Dubai, third was the Minsheng Bank Building in Wuhan which stands at 331 m, whilst fourth was The Address Downtown Burj Dubai (306 m). All in all, six of the ten tallest buildings completed in 2008 are located in Asia, three in the Middle East and one in North America.

Question: which is the tallest building in the world 2018?
Answer: Burj Khalifa in Dubai.
Burj Khalifa.