Antarctica is the coldest place on Earth, and surrounds the South Pole. Tourist visits are costly, demand physical fitness, can only take place in summer (from November to February), and are largely limited to the Peninsula, Islands and Ross Sea. A couple of thousand staff live here in summer in some four dozen bases mostly in those areas; a small number stay over winter. Inland Antarctica is a desolate plateau covered by 2–3 kilometres (1.2–1.9 mi) of ice. Occasional specialist air tours go inland, for mountaineering or to reach the Pole, which has a large base. Wildlife needs access to the sea and is confined to the coasts.