Tokelau, known previously as the Union Islands, and, until 1976, known officially as the Tokelau Islands, is a dependent territory of New Zealand in the southern Pacific Ocean. It consists of three tropical coral atolls: Atafu, Nukunonu, and Fakaofo. They have a combined land area of 10 km2 (4 sq mi). The capital rotates yearly among the three atolls. Tokelau lies north of the Samoan Islands, east of Tuvalu, south of the Phoenix Islands, southwest of the more distant Line Islands, and northwest of the Cook Islands. Tokelau has the smallest economy of any sovereign nation, although it is a leader in renewable energy, being the first 100% solar powered nation in the world.