Australia, officially the Commonwealth of Australia,[12] is a sovereign country comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands. It is the largest country in Oceania and the world’s sixth-largest country by total area. The population of 26 million[6] is highly urbanised and heavily concentrated on the eastern seaboard.[13] Australia’s capital is Canberra, though its largest city is Sydney. The country’s other major metropolitan areas are Melbourne, Brisbane, Perth, and Adelaide.