Thule Air Base is the U.S. Armed Forces' northernmost installation, located 750 miles north of the Arctic Circle. Thule's arctic environment includes icebergs in North Star Bay, a polar ice sheet, and Wolstenholme Fjord — the only place on earth where three active glaciers join together. Thule Air Base is home to the 21st Space Wing's global network of sensors providing missile warning, space surveillance and space control to North American Aerospace Defense Command (NORAD) and Air Force Space Command (AFSPC).