Water Cube, also known as the National Aquatics Center, and nicknamed the Water Cube, is an aquatics center that was built alongside Beijing National Stadium in the Olympic Green for the swimming competitions of the 2008 Summer Olympics. Despite its nickname, the building is not an actual cube, but a cuboid (a rectangular box). Ground was broken on December 24, 2003, and the Center was completed and handed over for use on January 28, 2008. Swimmers at here broke 25 world records during the 2008 Olympics. 

Architecture of Water Cube

 In July 2003, the design of Water Cube was chosen from 10 proposals in an international architectural competition for the aquatic center project. Then the Water Cube was specially designed and built by a consortium made up of PTW Architects (an Australian architecture firm), Arup international engineering group, CSCEC (China State Construction Engineering Corporation), and CCDI (China Construction Design International) of Shanghai. The Water Cube's design was a Team Masterpiece: the Chinese partners felt a square was more symbolic to Chinese culture and its relationship to the Bird's Nest stadium, while the Sydney based partners came up with the idea of covering the 'cube' with bubbles, symbolising water. It should be noted that contextually the cube symbolises earth whilst the circle (represented by the stadium) represents heaven.

 Comprising a steel space frame, it is the largest ETFE clad structure in the world with over 100,000 m² of ETFE pillows that are only 0.2 mm (1/125 of an inch) in total thickness. The ETFE cladding allows more light and heat penetration than traditional glass, resulting in a 30% decrease in energy costs.

 The outer wall of Water Cube is based on the Weaire–Phelan structure, a structure devised from the natural formation of bubbles in soap foam. The complex Weaire–Phelan pattern was developed by slicing through bubbles in soap foam, resulting in more irregular, organic patterns than foam bubble structures proposed earlier by the scientist Kelvin. Using the Weaire–Phelan geometry, the Water Cube's exterior cladding is made of 4,000 ETFE bubbles, some as large as 9.14 meters (30 feet) across, with seven different sizes for the roof and 15 for the walls.