Garden Island is a narrow island about 5 kilometers off the coast of Western Australia, connected by an artificial causeway and bridge. It is a limestone outcrop covered by a thin coating of sand accumulated during a period of lower sea levels, similar to Rottnest Island and Carnac Island. The Noongar peoples talk about walking to these islands in their Dreamtime. The water level increased at the conclusion of the last glacial period, cutting the island off from the mainland. The island has been relatively isolated for the last seven thousand years. Fleet Facility West, the Royal Australian Navy’s main fleet base, is located on the southeastern coast of Garden Island. A colony of tammar wallabies lives on Garden Island.