- Australia has a population of over 20 million people as of 2006, with the majority of the population between 15-64 years old. Christianity is the dominant religion. - English is the primary language of Australia, though Chinese and Italian are also commonly spoken. Sydney has a population of over 4 million people and a relatively low population density compared to other major cities. - When visiting Australia, travelers should apply for a visa, pack appropriate clothing for the weather, bring a camera, exchange money for Australian dollars, and research attractions in their destination city. It is also recommended to travel with companions and pack any necessary medical supplies.