The first human habitation of Australia is estimated to have occurred between 42,000 and 48,000 years ago. The first Australians were the ancestors of the current Indigenous Australians (Aborigines); they arrived via land bridges and short sea-crossings from present-day Southeast Asia. Most of these people were hunter-gatherers, with a complex oral culture and spiritual values based on reverence for the land and a belief in the Dreamtime. The Torres Strait Islanders, ethnically Melanesian, inhabited the Torres Strait Islands and parts of far-north Queensland; their cultural practices are distinct from those of the Aborigines.
The first undisputed recorded European sighting of the Australian mainland was made by the Dutch navigator Willem Janszoon, who sighted the coast of Cape York Peninsula in 1606. During the 17th century, the Dutch charted the whole of the western and northern coastlines of what they called New Holland, but made no attempt at settlement. In 1770, James Cook sailed along and mapped the east coast of Australia, which he named New South Wales and claimed for Britain. The expedition’s discoveries provided impetus for the establishment of a penal colony there. The British Crown Colony of New South Wales started with the establishment of a settlement at Port Jackson by Captain Arthur Phillip on 26 January 1788. This date was later to become Australia’s national day, Australia Day. Van Diemen’s Land, now known as Tasmania, was settled in 1803 and became a separate colony in 1825. The United Kingdom formally claimed the western part of Australia in 1829. Separate colonies were created from parts of New South Wales: South Australia in 1836, Victoria in 1851, and Queensland in 1859. The Northern Territory (NT) was founded in 1911 when it was excised from the Province of South Australia. South Australia was founded as a “free province” - that is, it was never a penal colony. Victoria and Western Australia were also founded “free”, but later accepted transported convicts. The transportation of convicts to the colony of New South Wales ceased in 1848 after a campaign by the settlers.
The Indigenous Australian population, estimated at about 350,000 at the time of European settlement, declined steeply for 150 years following settlement, mainly because of infectious disease combined with forced re-settlement and cultural disintegration. The removal of children, that some historians and Indigenous Australians have argued could be considered to constitute genocide by some definitions, may have made a contribution to the decline in the indigenous population.

On 1 January 1901, federation of the colonies was achieved after a decade of planning, consultation and voting, and the Commonwealth of Australia was born, as a Dominion of the British Empire.
Australia willingly participated in World War I; many Australians regard the defeat of the Australian and New Zealand Army Corps (ANZAC’s) at Gallipoli as the birth of the nation - its first major military action. The Statute of Westminster 1931 formally ended most of the constitutional links between Australia and the United Kingdom when Australia adopted it in 1942.
The shock of the United Kingdom’s defeat in Asia in 1942 and the threat of Japanese invasion caused Australia to turn to the United States as a new ally and protector. Since 1951, Australia has been a formal military ally of the US under the auspices of the ANZUS treaty.
Final constitutional ties between Australia and the United Kingdom were severed in 1986 with the passing of the Australia Act 1986, ending any British role in the Australian States,

Australia’s 7,686,850 square kilometres (2,967,909 sq. mi) landmass is on the Indo- Australian Plate. Surrounded by the Indian, Southern and Pacific oceans, Australia is separated from Asia by the Arafura and Timor seas. Australia has a total 25,760 kilometres (16,007 mi) of coastline and claims an extensive Exclusive Economic Zone of 8,148,250 square kilometres (3,146,057 sq. mi). This exclusive economic zone does not include the Australian Antarctic Territory.
The Great Barrier Reef, the world’s largest coral reef, lies a short distance off the northeast coast and extends for over 2,000 kilometres (1,250 mi). The world’s largest monolith, Mount Augustus, is located in Western Australia. At 2,228 metres (7,310ft), Mount Kosciuszko on the Great Dividing Range is the highest mountain on the Australian mainland, although Mawson Peak on the remote Australian territory of Heard Island is taller at 2,745 metres (9,006 ft).
By far the largest part of Australia is desert or semi-arid. Australia is the driest inhabited continent, the flattest, and has the oldest and least fertile soils. Only the south-east and south-west corners of the continent have a temperate climate. The majority of the population lives along the temperate southeastern coastline. The northern part of the country, with a tropical climate, has vegetation consisting of rainforest, woodland, grassland, mangrove swamps and desert. Climate is highly influenced by ocean currents, including the El Niño southern oscillation, which is correlated with periodic drought, and the seasonal tropical low pressure system that produces cyclones in northern Australia.

Great Barrier Reef