In 1950 Denmark agreed to allow the US to reestablish Thule Air Base in Greenland ; it was greatly expanded between 1951 and 1953 as part of a unified NATO Cold War defense strategy . The local population of three nearby villages was moved more than 100 kilometres ( 62 mi ) away in the winter . The United States tried to construct a subterranean network of secret nuclear missile launch sites in the Greenlandic ice cap , named Project Iceworm . It managed this project from Camp Century from 1960 to 1966 before abandoning it as unworkable . The Danish government did not become aware of the program 's mission until 1997 , when they discovered it while looking for records related to the crash of a nuclear-equipped B-52 bomber at Thule in 1968
crash
1968 Thule Air Base B-52 crash
Greenland