Australia has a population of around 27 million, concentrated in a handful of coastal cities. Sydney and Melbourne together account for more than 40% of the population; vast inland regions are nearly empty. It is one of the most urbanised countries on earth, despite its enormous size.
Aboriginal and Torres Strait Islander peoples were the first Australians, with archaeological evidence of continuous occupation dating back at least 50,000–65,000 years — one of the oldest cultures on earth. They comprise about 3.7% of the population today (around 900,000 people), with the largest communities in New South Wales, Queensland, and the Northern Territory. In the NT, Indigenous people make up nearly a third of the population. More than 150 Indigenous languages are still spoken.
Modern Australia is a heavily migrant nation. The first wave of non-Indigenous settlers after 1788 was British and Irish, many transported as convicts. The Gold Rush of the 1850s brought Chinese and other immigrants. After World War II, successive migration programs brought southern Europeans, then Southeast Asians, and today a steady flow from India, China, the Philippines, and elsewhere. About 30% of Australians were born overseas.
The culture is casual, direct, and inclined toward understatement. Australians have a particular affection for cutting down anyone who appears too self-important — it's called "tall poppy syndrome." Sport is a national religion; football (in four different codes depending on the state), cricket, and swimming are deeply embedded in the culture. The beach, the backyard barbecue, and the pub all carry cultural weight beyond simple leisure.
English is the national language, spoken natively by the vast majority. Australian slang ("arvo" for afternoon, "servo" for service station, "brekky" for breakfast) can initially seem impenetrable to new arrivals, but people are generally happy to explain.