Australia's biggest attraction is its natural beauty. The landscape varies from endless sunbaked horizons to dense tropical rainforest to chilly southern beaches. Scattered along the coasts, its cities blend a European enthusiasm for art and food with a laid-back love of sport and the outdoors.  Visitors expecting to see an opera in Sydney one night and meet Crocodile Dundee the next will have to re-think their grasp of geography in this huge country. It is this sheer vastness that gives Australia - and its diverse population - much of its character.