Also known as the National Aquatics Center, it 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). Comprising a steel space frame, it is the largest ETFE clad structure in the world with over 100,000 m' of ETFE 'pillows'. The ETFE cladding allows more light and heat penetration than traditional glass, resulting in a 30% decrease in energy costs. The outer wall is based on the Weaire-Phelan structure, a structure devised from the natural formation of bubbles in soap lather. The design was chosen in a competition and created by an Australian and Chinese consortium. After the Olympics, the building is now undergoing a 200 million Yuan revamp to turn the inside into a water park.