With a land area of 7.7million square kms, Australia is the 6th largest nation in the world - only marginally smaller than mainland USA, measuring some 4000kms (2500 miles) east to west and 3200km (2000miles) north to south.
A large part of Australia's appeal is its geographic diversity and wide open spaces. This in turn means that travelling between attractions can also span large distances. Perth to Sydney for example is approximately 5 hours flight, 5 days in a car or 3 nights on a train. The Great Barrier Reef is the same area as the UK and Ireland, and the state of Western Australia is the same size as Western Europe. For this reason, internal flights are often the best means of travelling between attractions and regional centres to maximise time at the destination.