The largest country in the geographical/geopolitical continent of Oceania is Australia, which makes up about nine-tenths of it's total land mass. It's only sizable neighbours are Papua New Guinea, New Zealand and Indonesia, of which only about a quarter of it's territory is situated in Oceania, with the rest in Asia. The Australian mainland is considered the World's smallest continent, and it is often described as the World's largest island too. Surrounded by the Indian and Pacific oceans, Australia is covered in the most part by a desert known as the outback, and it is the flattest, driest and least fertile continental block on Earth.