Canton Tower , formerly known as Guangzhou TV Astronomical and Sightseeing Tower and also known as Guangzhou Tower , is a tall multi-purpose observation tower in the Haizhu District of Guangzhou (historically known as Canton or Kwangchow), Guangdong, China. The tower was topped out in 2009 and it became operational on 29 September 2010 for the 2010 Asian Games. The tower briefly held the title of tallest tower in the world, replacing the CN Tower, before being surpassed by the Tokyo Skytree. It was the tallest structure in China prior to the topping out of Shanghai Tower on 3 August 2013. It is now the third tallest tower and the fifth-tallest freestanding structure in the world.