Yahoo News How the 'half a mile high' Burj Khalifa became the world’s tallest building
This article is part of Yahoo's 'On This Day' series
The world’s tallest building has turned 12 years old.
On 4 January 2010, the Burj Khalifa in Dubai was officially opened, standing at 829.8m (2,772ft), more than half a mile high.
It has held on to its title of world’s tallest building since its inauguration, and is 150m higher than its nearest challenger.
It was opened despite not being completed on the inside, and there was another surprise: it changed its name.
During construction, the building had been known as the Burj Dubai, but was renamed the Burj Khalifa after Abu Dhabi’s ruler, Sheikh Khalifa bin Zayed bin Sultan Al Nahyan.
Abu Dhabi had bailed out the building project, to the cost of more than £6bn, to help it pay off its debts just weeks before the opening.
Dubai’s ruler, Sheikh Mohammed bin Rashid Al Maktoum, said at the time: "This great project deserves to carry the name of a great man. Today I inaugurate Burj Khalifa.”
Watch: Burj Khalifa lights up with fireworks as Dubai celebrates New Year
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The tower contains residential, commercial, shopping and hotel space, and construction began in 2004.
It was designed by US architect Adrian Smith, who also designed the building aiming to trump the Burj Khalifa as the world’s tallest. However, construction of the Jeddah Tower in Saudia Arabia, which is earmarked to be the world’s first 1km high building, is currently on hold.
The nearest existing challengers to the Burj Khalifa are the Merdeka 118 in Kuala Lumpur, Malaysia, which is 678m tall, and the Shanghai Tower in China, at 632m.
The Burj Khalifa’s structural engineer, Bill Baker, said when it opened: "We weren't sure how high we could go. It was kind of an exploration, a learning experience."
The Burj Khalifa has 163 floors - however, its observation decks, ironically named At The Top, are on the 124th, 125th and 148th floors.
The building boasts the world’s highest nightclub on its 144th floor.
The structure has more than 24,300 windows, covering some 120,000 square metres of glass.
The Burj Khalifa was famously climbed by actor Tom Cruise as part of filming for the 2011 movie Mission: Impossible - Ghost Protocol.
It has also been scaled by French rock climber Alain “Spider-Man” Robert, who climbed to the top of the spire in six hours, using a rope and harness.
