Hall Island, with its spectacular thousand-foot-high cliffs, lies close to the larger St Matthew Island in the Bering Sea. The islands of the Bering Sea represent a small but unique Arctic maritime environment. Tundra-covered and surrounded by sea ice in winter they serve as protected refuges for the world's largest herds of fur-bearing seals and sea otters, as well as sea lions and walrus. Hall Island also has thousand of breeding birds including Fulmar, Kittiwake, Bruennich's Guillemot and Puffin.