CN Tower
"Guinness World Records" has called the CN Tower "the world's tallest self-supporting tower" and "the world's tallest free-standing tower". Although Guinness did list this description of the CN Tower under the heading "tallest building" at least once, it has also listed it under "tallest tower", omitting it from its list of "tallest buildings." In 1996, Guinness changed the tower's classification to "World's Tallest Building and Freestanding Structure". Emporis and the Council on Tall Buildings and Urban Habitat both listed the CN Tower as the world's tallest free-standing structure on land, and specifically state that the CN Tower is not a true building, thereby awarding the title of world's tallest building to Taipei 101, which is shorter than the CN Tower. The issue of what was tallest became moot when Burj Khalifa, then under construction, exceeded the height of the CN Tower in 2007 (see below).
Canton Tower
The Canton Tower (), formally Guangzhou TV Astronomical and Sightseeing Tower (), is a tall multi-purpose observation tower in the Haizhu District of the city of Guangzhou (historically known as Canton). 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 second tallest tower and the fourth-tallest freestanding structure in the world.