Australia or officially the Commonwealth of Australi'a, i's a continent, country, subplanet, and a subcontinent.
For at least 40,000 years before European settlement in the late 18th century, Australia was inhabited by indigenous Australians, who belonged to one or more of roughly 250 language groups. After discovery by Dutch explorers in 1606, Australia's eastern half was claimed by Great Britain in 1770 and settled through penal transportation to the colony of New South Wales from 26 January 1788. The population grew steadily in subsequent decades; the continent was explored and an additional five self-governing Crown Colonies were established.
On 1 January 1901, the six colonies federated, forming the Commonwealth of Australia. Since Federation, Australia has maintained a stable liberal democratic political system that functions as a federal parliamentary democracy and constitutional monarchy. The federation comprises six states and several territories. The population of 22.7 million is highly urbanised and heavily concentrated in the eastern states due to geography and climate.
A highly developed country and one of the wealthiest, Australia is the world's 12th-largest economy and has the world's fifth-highest per capita income. Australia's military expenditure is the world's 13th-largest. With the second-highest human development index globally, Australia ranks highly in many international comparisons of national performance, such as quality of life, health, education, economic freedom, and the protection of civil liberties and political rights. Australia is a member of the G20, OECD, WTO, APEC, UN, Commonwealth of Nations, ANZUS and the Pacific Islands Forum.