The CTBUH, now called the Council on Vertical Urbanism (CVU), was formed in 1969. As of November 2026, it announces the title The World's Tallest Building and sets the standards by which buildings are measured. It keeps a list of the 100 tallest completed buildings in the world. Much of the Burj Khalifa's record height is a spire with almost no usable space. Its 244-meter spire is widely called vanity height. Without the spire the tower would be about 585 meters (1,919 feet) tall, still the tallest building to the highest occupied floor. Sometimes two towers dispute the title. In 1996, because people argued over whether the Petronas Towers or the Sears Tower was taller, the CTBUH began ranking buildings in four categories. The Petronas Towers' spires count toward their height but the Sears Tower's antennas do not, so the Petronas Towers ranked higher.

To count as the building's height, an entrance must be a significant one: above grade, open to the air, and leading to the building's main uses by elevator. Entrances reached through a below-grade sunken plaza are generally not recognized. The Willis Tower in Chicago has 108 stories counted by standard methods, but its owners count the main roof as 109 and the mechanical penthouse roof as 110. Counting rules like these are why published story numbers for the same building can differ. The Petronas Towers in Kuala Lumpur, Malaysia, are an interlinked pair of 88-story supertall skyscrapers standing 451.9 meters (1,483 feet) tall. From 1998 to 2004 they were the tallest buildings in the world, until Taipei 101 passed them.

Taipei 101 in Taiwan is 508 meters (1,667 feet) and 101 stories tall. It held the title of world's tallest building from 2004, and sources give 2009 or 2010 as the year the Burj Khalifa took over, as of November 2026. A tuned mass damper is a device in a structure that reduces vibrations. It is a mass mounted on springs, tuned to the structure's natural vibration rate, and it reduces the structure's maximum motion while weighing much less than the structure. Elisha Otis invented a safety device in 1853 that stops an elevator from falling if the hoisting cable breaks. On 23 March 1857 he installed the first safety elevator for passengers in a store in New York City. Safe elevators made buildings of more than four or five stories practical.

The Home Insurance Building weighed only one-third as much as a masonry building of the same size. City officials were so worried that it would fall that they halted construction while they investigated its safety. Before steel frames, tall buildings were held up by thick masonry walls, and masonry reached its practical limit in 1891 with Chicago's Monadnock Building. Architectural historians therefore defined the skyscraper by its steel skeleton, which made much taller buildings possible. Burnham and Root's 45-meter Rand McNally Building in Chicago (1889) was the first all-steel framed skyscraper. New York took the lead in the race for the tallest building by 1895 with the 103-meter American Surety Building, and held the title for many years.

The Burj Khalifa was called Burj Dubai until it opened in January 2010, when it was renamed. It is named after Sheikh Khalifa bin Zayed Al Nahyan, the former president of the United Arab Emirates. Shanghai Tower in China twists as it rises. Wind tunnel tests confirm that the twisting shape cuts structural wind loading by 24 percent compared with a rectangular building of the same height. A second glass skin around the whole tower also saves energy. As of November 2026, Merdeka Maybank Tower in Kuala Lumpur, Malaysia, is the second tallest building in the world, at 678.9 meters (2,227 feet) and 118 stories. It was completed in November 2023 and renamed on 30 July 2026 after one of its tenants, Maybank. As of November 2026, the Makkah Royal Clock Tower in Mecca is fourth, at 601 meters, with four huge clock faces.

Words to know

• vanity: for show
• masonry: stone or brick
• damper: vibration reducer
• antennas: radio masts