The Canton Tower standing 600m tall was built in Guangzhou in 2010. It's the tallest building in China and the 4th tallest in the world.
In late 2011 the attractions at the top of the tower opened. The outdoor observation deck at 488m up is the World's Highest public observation deck. The thrillllling Intamin Drop Tower, built 455m up is the World's Highest Thrill Ride, and is genuinely scary as hell.
There is also a spiral staircase called the Spider Walk that goes from the 32nd to the 64th floor.