Skyscrapers are beginning to make a comeback as global economic conditions improve.
Nearly 600 skyscrapers, at least 200 metres high, are under construction around the world.
Four of the tallest buildings under construction are in China, while the tallest in Dubai will be more than 1km high - a world first.
However, big buildings don't always mean big business.
Only six of the 72 floors in London's tallest building, the Shard, are occupied.
But Wall Street Journal reporter Peter Evans said companies don't always build them to fill them. Often they are just a status symbol and could signal economic disaster, rather than prosperity.