Permafrost Research Tunnel
Permafrost is the stuff of science fiction but it's real enough. The Cold Regions Research and Engineering Laboratory, a.k.a. CREEL, has set up shop in this long burrow which is embedded with prehistoric animals and plant remains. The surrounding permafrost is not actually frozen ice, it is a term for ground or frozen soil regardless of water content that stays a constant zero degrees Celsius or lower. This laboratory started in the 1960s is not officially open to the public - visitors must obtain permission first.