During the Cold War, a secret U.S. Army mission, at Camp Century in northwestern Greenland, drilled down through 4,560 feet of ice on the frozen island—and then kept drilling to pull out a twelve-foot-long tube of soil and rock from below the ice. Then this icy sediment was lost in a freezer for decades. It was accidentally rediscovered in 2017 and was shown to hold not just sediment but also leaves and moss, remnants of an ice-free landscape, perhaps a boreal forest.
