Burj Khalifa [Arab., = Khalifa Tower], skyscraper in Dubai, United Arab Emirates, that is the tallest building in the world. The centerpiece of a large urban development, it stands 2,717 ft (828 m) high and has 160 floors. Designed by American architect Adrian Smith of the firm Skidmore, Owings and Merrill, the structure has a triple-lobed footprint derived from a native flower and becomes more slender as it rises to its spire by means of staggered setbacks. The exterior, clad in reflective glazing, with aluminum and textured stainless-steel spandrel panels and vertical stainless-steel fins, has patterns derived from Islamic architecture. Construction of the tower began in 2004 and was completed in 2009; known as Burj Dubai while under construction, it was renamed when it opened in 2010. A mixed-use building, the tower contains a luxury hotel, residential apartments, corporate offices, and suites.