81. Skidmore, Owings & Merrill (SOM), Burj Khalifa,

also known as Burj Dubaï or Dubaï Tower, 2004-2010.

Height: 828 m. Dubaï (United Arab Emirates)

The tallest building on earth even before it was completed, the Burj Dubai skyscraper was designed by Adrian Smith, who worked with the American architectural firm SOM until 2006. The anticipated height of the tower was left vague during its construction, but it is expected to top out at over 800 metres. Containing offices, luxury residences and a hotel, it is part of the larger “Downtown Dubai” project meant to attract visitors and investors to this small but very wealthy emirate. The tower consists of a central core surrounded by three tall elements that form a series of spiraling setbacks as they rise: in this respect it generally resembles the bundled tube form of the Sears Tower in Chicago, also by SOM, as well as Frank Lloyd Wright’s proposal for a ‘Mile-High’ tower of the 1950s. The building’s three-lobed footprint is said to be derived from floral patterning in Islamic architecture. Its lower part has a frame of special pressure-and heat-resistant reinforced concrete; during the construction process this was mixed with ice and poured at night to allow even curing. The tower’s budget and construction methods have been a source of controversy, costing over 4 billion dollars.