Australia is bounded by the waters of the Pacific Ocean to the east, the Arafura Sea to the north, the Indian Ocean to the west, and the Southern Ocean to the south. It’s highest point on the mainland is Mount Kosciusko, at 2,228 m, in the Australian Alps.
 

It’s most fertile land is around the coastal regions, enclosing what is referred to as the Outback, memorable for it’s vivid colours of red, rich brown, yellows, orange, bluish-green of many scrub, and the linen-white trunks of ghost gum trees. This seemingly endless landscape is broken by salt lakes, mountains ranges such as the MacDonnell and Flinders Ranges and fantastic rock formations such as Uluru, Mt Olga, Twelve Apostles and the Three Sisters.

The longest river, originating in Queensland, is the Murray Darling measuring 2736 km.

The Australian federation consists of six States and two Territories. Most inland borders follow lines of longitude and latitude. The largest State, Western Australia, is about the same size as Western Europe.

Natural environment
Australian plants and animals evolved in isolation from other parts of the world and as a consequence have a remarkable diversity of life forms not seen elsewhere in the world. When the super-continent of Gondwanaland split up about 160 million years ago, Australia joined Antarctica and drifted towards the South Pole, where glaciers formed a barrier between it and other land masses. Over the past 45 million years, Australia has moved away from Antarctica towards the equator and become warmer and more arid. About 35 million years ago, eucalypts began to displace the dense forests of the cool, damp Tertiary era. Today Australian eucalypts account for more than half of all eucalypts found throughout the world.

The marsupials native to Australia have a different chromosome structure than mammals in other parts of the world. Typically, they suckle their young in a pouch. Like the eucalypts, marsupials occupied a wide range of ecological niches in Australia. The first kangaroo marsupials seem to have appeared about 15 million years ago. They vary enormously in size and adaptation. A species of tropical kangaroo lives in trees, but most kangaroos are tough, efficient users of dry bush.

As the world climate warmed and glaciers melted, oceans gradually rose to their current level and the land bridges to New Guinea and Tasmania were cut. Corals colonised a flooded coastal plain, forming the Great Barrier Reef of Queensland.

Ancient plants still grow in the wild. Large ‘Antarctic’ tree ferns are common in damp, shaded gullies on the south sides of ridges. Cycad palms form an understorey to tall, silvery spotted gums (eucalypts) along the south-east coast. Rare relics from earlier geological eras are found in small, special habitats, such as desert canyons. Pressure on native habitats from agriculture and introduced pests like the fox and rabbit have resulted in extinctions of some native species in the past 200 years. Australia now has a strong scientific and legal framework to deal with these issues. Australians generally care about their unique environment.