The Abraj Al Bait Towers in Mecca, Saudi Arabia, commonly referred to as the Mecca Royal Hotel Clock Tower. Its clock is visible from 17 kilometres away in the middle of the night and is six times bigger than London's Big Ben.
World's tallest buildings
One World Trade Center became the tallest building in the Western Hemisphere when a silver spire topping the building was installed on Friday, May 10. Here's a look at the world's tallest buildings.