Two airmen pause at the entrance to Base Operations, Thule Air Base, Greenland, circa early-to-mid 1950s. Bundled against the extreme Arctic cold in heavy fur-hooded parkas, they stand beneath the base's iconic elevation sign. Built beginning in 1951, Thule became a critical U.S. Strategic Air Command outpost during the Cold War, prized for its strategic position near the top of the world. Project: 218295