New Zealand is an island country in the southwestern Pacific Ocean. The country geographically comprises two main landmasses that of the North Island, or Te Ika-a-Ma-ui, and the South Island, or Te Waipounamu and numerous smaller islands. New Zealand is situated some 1,500 kilometres east of Australia across the Tasman Sea and roughly 1,000 kilometres south of the Pacific island areas 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 biodiversity of animal, fungal and plant life; most notable are the large number of unique bird species. The country's varied topography and its sharp mountain peaks owe much to the tectonic uplift of land and volcanic eruptions.