New Zealand is an archipelago in the southwestern Pacific Ocean. The country geographically comprises two main landmasses — the North Island (Te Ika-a-Māui) and the South Island (Te Waipounamu) — and over 700 smaller islands. It is the sixth-largest island country by area and lies east of Australia across the Tasman Sea and south of the islands of New Caledonia, Fiji, and Tonga. The country's varied topography and sharp mountain peaks, including the Southern Alps, owe much to tectonic uplift and volcanic eruptions. New Zealand's capital city is Wellington, and its most populous city is Auckland.