http://www.damninteresting.com/?p=750 Thanks to
David Glover.

During the Cold War, the US and the Soviets had an ongoing game of
tag taking place under the Arctic Ice Cap. Among the better-known technologies
employed in this chase, both sides often built "research stations" on the arctic
ice floes. Though there was a potential for real science to take place in such
locales, the purpose of these ramshackle huts was just to house hydrophones that
would track submarines ranging the Arctic Sea. A problem arose, however, in
manning these stations: they were beyond the limited range of the period's
helicopters, too far into the floe for icebreakers, and in areas that are
inhospitable to landing airplanes.