Window cleaning at the Burj Khalifa
This has been a landmark year for the world's skyscrapers. Despite the global financial crisis, 2012 saw the unveiling of Europe's new tallest building, the Shard in London - and by the end of the year, nearly three-quarters of the world's 100 tallest buildings will be located in Asia and the Middle East, a dramatic shift from west to east.
With more than 160 storeys to contend with, the maintenance team at Dubai's Burj Khalifa - the tallest building in the world - have their hands full, around the clock.
Simon Atkinson went to find out what it takes to keep the world's tallest building running smoothly - from dealing with waste to keeping the windows clean.
- From the section World