Iceland is a European island country in the North Atlantic Ocean on the Mid-Atlantic Ridge. The capital and largest city is Reykjavík, with the surrounding areas in the southwestern region of the country being home to some two-thirds of the national population. Iceland is volcanically and geologically active. The interior mainly consists of a plateau characterized by sand fields, mountains and glaciers, while many glacial rivers flow to the sea through the lowlands. Iceland is warmed by the Gulf Stream and has a temperate climate despite a high latitude just outside the Arctic Circle.