New Guinea (also, Tok Pisin: Niugini, Dutch: Nieuw-Guinea, and Indonesian: Irian; historically: Papua) is the world's second largest island, after Greenland, covering a land area of 786,000 km². Located in the southwest Pacific Ocean, it lies to the east of the Malay Archipelago, with which it is sometimes included as part of a greater Indo-Australian Archipelago. Geologically it is a part of the same tectonic plate as Australia. When world sea levels were low, the two shared shorelines (which now lie 100 to 140 metres below sea level), combining with lands now inundated into the tectonic continent of Sahul, also known as Greater Australia. The two landmasses became separated when the area now known as the Torres Strait flooded after the end of the last glacial period. Anthropologically, New Guinea is considered part of Melanesia. Politically, the western half of the island comprises two Indonesian provinces: Papua and West Papua. The eastern half forms the mainland of the country of Papua New Guinea. The island has a population of about 7.5 million, with a very low population density of only 8 inh/km².