Milestones ( Link from Wikipedia)
February 2004: Piling starts.
21 September 2004: Emaar contractors begin construction.
March 2005: Structure of Burj Khalifa starts rising.
June 2006: Level 50 is reached.
February 2007: Surpasses the Sears Tower as the building with the most floors.
13 May 2007: Sets record for vertical concrete pumping on any building at 452 m (1,483 ft), surpassing the 449.2 m (1,474 ft) to which concrete was pumped during the construction of Taipei 101, while Burj Khalifa reached the 130th floor.
21 July 2007: Surpasses Taipei 101, whose height of 509.2 m (1,671 ft) made it the world's tallest building, and level 141 reached.
12 August 2007: Surpasses the Sears Tower antenna, which stands 527.3 m (1,730 ft).
12 September 2007: At 555.3 m (1,822 ft), becomes the world's tallest freestanding structure, surpassing the CN Tower in Toronto, and level 150 reached.
7 April 2008: At 629 m (2,064 ft), surpasses the KVLY-TV Mast to become the tallest man-made structure, level 160 reached
17 June 2008: Emaar announces that Burj Khalifa's height is over 636 m (2,087 ft) and that its final height will not be given until it is completed in September 2009.
1 September 2008: Height tops 688 m (2,257 ft), making it the tallest man-made structure ever built, surpassing the previous record-holder, the Warsaw Radio Mast in Konstantynów, Poland.
17 January 2009: Topped out at 829.84 m (2,723 ft).
1 October 2009: Emaar announces that the exterior of the building is completed.
4 January 2010: Burj Khalifa's official launch ceremony is held and Burj Khalifa is opened. Burj Dubai renamed Burj Khalifa in honour of the President of the UAE and ruler of Abu Dhabi, Sheikh Khalifa bin Zayed al Nahyan.
10 March 2010 Council on Tall Buildings and Urban Habitat (CTBUH) certifies Burj Khalifa as world's tallest building.