Burj Khalifa known as Burj Dubai prior to its inauguration, is a skyscraper in Dubai, United Arab Emirates, and is currently the tallest manmade structure in the world, at 829.84 m (2,723 ft).Construction began on 21 September 2004, with the exterior of the structure completed on 1 October 2009. The building officially opened on 4 January 2010, and is part of the new 2 km2 (490-acre) flagship development called Downtown Dubai at the 'First Interchange' along Sheikh Zayed Road, near Dubai's main business district. The tower's architecture and engineering were performed by Skidmore, Owings and Merrill of Chicago, with Adrian Smith as chief architect, and Bill Baker as chief structural engineer. The primary contractor was Samsung C&T of South Korea.
The total cost for the project was about US$1.5 billion; and for the entire "Downtown Dubai" development, US$20 billion. In March 2009, Mohamed Ali Alabbar, chairman of the project's developer, Emaar Properties, said office space pricing at Burj Khalifa reached US$4,000 per sq ft (over US$43,000 per m²) and the Armani Residences, also in Burj Khalifa, sold for US$3,500 per sq ft (over US$37,500 per m²).
The project's completion coincided with the global financial crisis of 2007–2010, and with vast overbuilding in the country, led to high vacancies and foreclosures. With Dubai mired in debt from its huge ambitions, the government was forced to seek multibillion dollar bailouts from its oil rich neighbor Abu Dhabi. Subsequently, in a surprise move at its opening ceremony, the tower was renamed Burj Khalifa, said to honour the UAE President Khalifa bin Zayed Al Nahyan for his crucial support.
Due to the slumping demand in Dubai's property market, the rents in the Burj Khalifa plummeted 40% some ten months after its opening. Out of 900 apartments in the tower, around 825 were still empty at that time.

Awards
In June 2010, Burj Khalifa was the recipient of the 2010 Best Tall Building Middle East & Africa award by the Council on Tall Buildings and Urban Habitat.On 28 September 2010 Burj Khalifa won the award for best project of year at the Middle East Architect Awards 2010.
The Council on Tall Buildings and Urban Habitat bestowed a new award for Burj Khalifa at its annual “Best Tall Buildings Awards Ceremony” on 25 October 2010 when Burj Khalifa honored as first recipient of CTBUH’s new Tall Building “Global Icon” Award. According to CTBUH the new “Global Icon” award recognizes those very special supertall skyscrapers that make a profound impact, not only on the local or regional context, but on the genre of tall buildings globally. Which is innovative in planning, design and execution, the building must have influenced and reshaped the field of tall building architecture, engineering, and urban planning. It is intended that the award will only be conferred on an occasional basis, when merited by an exceptional project perhaps every ten or fifteen years.
CTBUH Awards Chair Gordon Gill, of Adrian Smith + Gordon Gill Architecture said:
"There was discussion amongst members of the jury that the existing ‘Best Tall Building of the Year’ award was not really appropriate for the Burj khalifa. We are talking about a building here that has changed the landscape of what is possible in architecture a building that became internationally recognized as an icon long before it was even completed. ‘Building of the Century’ was thought a more appropriate title for it."

BASE jumping
The building has been used by several experienced BASE jumpers for both authorized and unauthorized BASE jumping:

• In May 2008, Hervé Le Gallou and a British man (name unknown) dressed as engineers, illegally infiltrated Burj Khalifa (around 650 m at the time), and jumped off a balcony situated a couple of floors below the 160th floor.
• On 8 January 2010, with permission of the authorities, Nasr Al Niyadi and Omar Al Hegelan, from the Emirates Aviation Society, broke the world record for the highest BASE jump from a building after they leapt from a crane suspended platform attached to the 160th floor at 672 m (2,205 ft). The two men descended the vertical drop at a speed of up to 220 km/h (140 mph), with enough time to open their parachutes 10 seconds into the 90 second jump.

Climbing
On 28 March 2011, Alain Robert scaled the outside of Burj Khalifa. The climb to the top of the spire took six hours. To comply with UAE safety laws Robert, who usually climbs in free solo style, took the unusual step of using a rope and harness for the climb.
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