Australia is an island continent located in the Southern Hemisphere. Its capital is Canberra, and its largest cities are Sydney, Melbourne, Brisbane, and Perth. Australia was originally inhabited by Aboriginal Australians for over 40,000 years before European settlement began in the 18th century. Today, Australia has a population of over 22 million people and is known for its unique wildlife such as kangaroos and koalas, as well as landmarks like the Sydney Opera House and Uluru.