Its personnel were officially stationed there to test Arctic construction methods and carry out research. Scientists based at the camp did, indeed, drill the first ice core samples ever used to study the earths climate, obtaining data still cited today, according to William Colgan, a climate and glacier scientist from the Lassonde school of engineering at Torontos York University, and the lead author of the study.

In reality, the camp served as cover for something altogether different - a project so immense and so secret that not even the Danish government was informed of its existence.

They thought it would never be exposed, said Colgan. Back then, in the 60s, the term global warming had not even been coined. But the climate is changing, and the question now is whether whats down there is going to stay down there.

The study suggests it is not.

Project Iceworm, presented to the US chiefs of staff in 1960, aimed to use Camp Centurys frozen tunnels to test the feasibility of a huge launch site under the ice, close enough to fire nuclear missiles directly at the Soviet Union.

From 1964 Camp Century was used only intermittently, and three years later it was abandoned altogether, the departing soldiers taking the reaction chamber of the nuclear generator with them.

They left the rest of the camps infrastructure and its biological, chemical and radioactive waste where it was, on the assumption it would be preserved for eternity by the perpetually accumulating snow and ice.

Thus far their assumption has proven correct. Up to 12 metres deep at the time it was abandoned, the ice covering Camp Century has since thickened to around 35 metres and will continue to deepen for a while yet. However, climate change is set to reverse that process.