australia is the sixth largest country in the world. eighty-five per cent of people live in the big cities, so you can travel for thousands of kilometers and never see anyone. outside the cities, the land in australia is mainly hot desert. this is called the outback. in some parts of the outback, there aren't any schools. so children learn from the school of the air - by radio, email and television. and when people in the outback are ill. their doctor visits them by plane - the "flying doctor".