The National Aquatics Center(the Water Cube) is just next to the Bird Nest. The National Swimming Center is the only important Olympic venue that is built by donations from compatriots from Hong Kong and Macao. It has a total floor space of 50,000 square meters with a seating capacity of 17,000. The whole project costs about US$100 million. The center was used for swimming, diving, synchronized swimming and water-polo games during the Olympic Games 2008. After the games, the center has turned into a large water recreational center open to the public. It is dubbed "cube" because of its semi-transparent "bubbles" spread out all over its surface with a shape very similar to the structure of "H2O".