In the late 1950s, during the height of the Cold War, the US military constructed a secret base in the Arctic for "research" purposes.
Some theorists claim that it was actually used as a covert nuclear weapons storage and/or testing facility.
Others have made even grander claims - that Camp Century was actually a weather manipulation experiment ... or a U.S. Military administered Alien / UFO base!
The whole truth might never be known.
This is the actual declassified US ARMY FILM documenting the construction process.