The Rock Islands of Palau, also called Chelbacheb, are a small collection of limestone or coral uprises, ancient relics of coral reefs that violently surfaced to form Islands in Palau's Southern Lagoon, between Koror and Peleliu, and are now an incorporated part of Koror State. There are between 250 to 300 islands in the group according to different sources, with an aggregate area of 47 square kilometres (18 sq mi) and a height up to 207 metres (679 ft). They are a World Heritage Site since 2012.