A marine park is a park consisting of an area of sea (or lake) sometimes protected for recreational use, but more often set aside to preserve a specific habitat and ensure the ecosystem is sustained for the organisms that exist there. Most marine parks are designated by governments, and organized like 'watery' national parks. The largest marine park used to be the Great Barrier Reef Marine Park in Australia, at 350,000 km² until 2010, when the United Kingdom announced the opening of the Chagos Marine Park or Chagos Archipelago.