Project Iceworm was a top secret United States Army program of the Cold War, which aimed to build a network of mobile nuclear missile launch sites under the Greenland ice sheet. The ultimate objective of placing medium-range missiles under the ice — close enough to strike targets within the Soviet Union — was kept secret from the Government of Denmark. To study the feasibility of working under the ice, a highly publicized "cover" project, known as Camp Century, was launched in 1960. Unstable ice conditions within the ice sheet caused the project to be canceled in 1966.
Details of the missile base project were secret for decades, but first came to light in January 1995 during an enquiry by the Danish Foreign Policy Institute (DUPI) into the history of the use and storage of nuclear weapons in Greenland. The enquiry was ordered by the Parliament of Denmark following the release of previously classified information about the 1968 Thule Air Base B-52 crash that contradicted previous assertions by the Government of Denmark.
To test the feasibility of construction techniques a project site called "Camp Century" was started by the United States military, located at an elevation of 6,600 feet (2,000 m) in Northwestern Greenland, 150 miles (240 km) from the American Thule Air Base. The radar and air base at Thule had already been in active use since 1951.