Sentosa Island, known mononymously as Sentosa, is an island located off the southern coast of Singapore's main island. The island is separated from the main island of Singapore by a channel of water, the Keppel Harbour, and is adjacent to Pulau Brani, a smaller island wedged between Sentosa and the main island. Formerly used as a British military base and afterwards as a Japanese prisoner-of-war camp, the island was renamed Sentosa in the 1970s to become a popular tourist destination.