The Burj Khalifa is a skyscraper in Dubai, United Arab Emirates. It is the world's tallest structure. With a total height of 829.8 m and a roof height of 828 m, the Burj Khalifa has been the tallest structure and building in the world since its topping out in 2009, supplanting Taipei 101, the previous holder of that status. Construction of the Burj Khalifa began in 2004, with the exterior completed five years later in 2009.