Canton Tower, formerly Guangzhou TV Astronomical and Sightseeing Tower is an 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 in 2011. It is the tallest structure in China and the fourth-tallest freestanding structure in the world. It is named after the traditional European name of the city.
The form, volume and structure of the towers is generated by two ellipses, one at foundation level and the other at a horizontal plane at 450 m (1,480 ft). These two ellipses are rotated relative to another. The tightening caused by the rotation between the two ellipses forms a "waist" and a densification of material halfway up the tower.This means that the lattice structure, which at the bottom of the tower is porous and spacious, becomes denser at waist level. The waist itself becomes tight, like a twisted rope; transparency is reduced and views to the outside are limited. Further up the tower the lattice opens again, accentuated here by the tapering of the structural column-tubes.
The rooftop has an outdoor public observatory 488 m (1,601 ft) above the ground, which takes the form of a terraced elliptical space, roughly the size of a small city square. Opened in December 2011, it is currently the highest and largest outdoor observation deck in the World. Sixteen transparent "crystal" passenger cars, each with a diameter of 3.2 m (10 ft) and able to carry four to six people, travel on a track round the edge of the tower's roof, taking between 20 and 40 minutes to circumnavigate the rooftop. The installation is described by the media as a ferris wheel; however, its passenger cars are not suspended from the rim of a wheel and remain horizontal without being fully rotated, and the track, which follows the incline of the roof, is closer to the horizontal than the vertical.
At night, the tower glows and emits light, rather than being uplit. Every node in the lighting design is individually controllable to allow for animations and colour changes across the entire height of the tower. As all lighting is based on LED technology and all fixtures are located on the structure itself, the lighting scheme consumes only 15% of the allowed maximum for facade lighting.