New Zealand (Māori: Aotearoa) is an island country in the south-western Pacific Ocean comprising two main landmasses (the North Islandand the South Island) and numerous smaller islands. The country is situated some 1,500 kilometres (900 mi) east of Australia across theTasman Sea, and roughly 1,000 kilometres (600 mi) south of the Pacific island nations of New Caledonia, Fiji, and Tonga. Because of its remoteness, it was one of the last lands to be settled by humans. During its long isolation New Zealand developed a distinctive faunadominated by birds, many of which became extinct after the arrival of humans and introduced mammals. With a mild maritime climate, the land was mostly covered in forest. The country's varied topography and its sharp mountain peaks owe much to the uplift of land and volcanic eruptions caused by the Pacific and Indo-Australian Plates clashing underfoot.