The U.S. military established a nuclear base, known as Camp Century, under the ice in Greenland, which has remained hidden for decades. This base was part of the Army's nuclear power program and housed the PM-2A nuclear reactor, which was designed to provide power for military operations in remote locations. Recent discussions among users reflect their fascination with its historical significance, technology, and the current state of the base as it is buried under melting ice due to climate change. Links to related documentaries and detailed information about the reactor and the camp have been shared in the comments.