Australia. Australia, officially the Commonwealth of Australia, is a country comprising the mainland of the Australian continent, the island of Tasmania and numerous smaller islands. Australia has a total area of 7,688,287 km2 (2,968,464 sq mi), making it the sixth-largest country in the world and the largest in Oceania. It is the world's oldest, flattest, and driest inhabited continent, with some of the least fertile soils. It is a megadiverse country, and its size gives it a wide variety of landscapes and climates including deserts in the interior and tropical rainforests along the coast. The ancestors of Aboriginal Australians began arriving from south-east Asia 50,000 to 65,000 years ago, during the last glacial period. By the time of British settlement, Aboriginal Australians spoke 250 distinct languages and had the oldest living culture in the world. Australia's written history commenced with Dutch exploration of most of the...