Australia is the world's sixth-largest country and one of the most geographically extreme — a continent-island stretching from tropical rainforest and coral reef to red desert and alpine snowfields. You cannot see it all in one trip. Most people see a corner and leave wanting to return.
The east coast is where most international visitors spend their time, and with reason: Sydney, the Great Barrier Reef, and the Daintree rainforest are all here, connected by a well-trodden backpacker route. Sydney anchors the south; Cairns the north. Brisbane, the Gold Coast, and Noosa lie in between. This route is heavily visited but it has the infrastructure to handle it.
The Red Centre — Uluru, Kata Tjuta, and the MacDonnell Ranges — is Australia's spiritual and geographical heart. It requires a deliberate detour (the nearest city is Alice Springs, itself remote), but the effort is rewarded. The colours at sunrise and sunset, the absolute silence, and the depth of Aboriginal culture associated with the landscape make it unlike anywhere else.
Victoria is the most densely populated state and arguably the most culturally rich. Melbourne has exceptional food, excellent museums, and a European ambience unlike any other Australian city. The Great Ocean Road, the Yarra Valley, and the alpine parks are all within a day's drive.
South Australia punches above its weight. Adelaide has the best arts festival on the continent and easy access to the Barossa Valley and McLaren Vale wine regions. The Flinders Ranges offer outback scenery without the extreme distances of the Northern Territory.
Tasmania is overlooked by most international visitors, which makes it all the more appealing. Wilderness hiking, outstanding seafood, remarkable whisky, and a distinctive convict heritage make it a destination in its own right.
Western Australia is vast and sparsely populated. Perth is a confident, pleasant city with good beaches and an easy pace. The Margaret River wine region (south) and the Kimberley (north — remote, expensive to reach, extraordinary) are the main draws beyond the city.