Australia is the 6th largest country in the world by size, larger than Europe, with a population of 23 million made up of immigrants from around the world and Aboriginal people who have lived there for over 40,000 years. The capital is Canberra, the Australian dollar is used, and English is the official language. The country has diverse climates ranging from desert in the central Outback to forests, mountains and tropical conditions in other areas, and seasons are opposite of the northern hemisphere with summer from December to February.