Rabaul (räˈboul) [key], town (1990 pop. 17,044), on New Britain island, Bismarck Archipelago, a part of Papua New Guinea. Situated within an active caldera surrounded by volcanoes, the city has long been vulnerable to volcanic eruptions. It was nearly destroyed in 1937, but after being rebuilt Rabaul flourished as the principal city and port of the archipelago, with one of the finest harbors in the world. Copra was the chief export. In 1994 the city was again devastated by volcanic eruptions, which buried its eastern end in ash and mud and filled the harbor with debris. The rest of the city and the surrounding area was also severely damaged, and the capital of East New Britain prov., which was formerly in the city, was moved to Kokopo. Rabaul was the capital of the Australian Territory of New Guinea from 1920 to 1941. During World War II, it was the major Japanese naval and air base for the projected invasion of Australia. Totally destroyed by Allied bombing, it was rebuilt after the war.