While flying roughly 150 miles east of northern Greenland’s Pituffik Space Base, the NASA researchers also snapped photos of the polar landscape from the plane’s windows showing a barren, icy expanse. It wasn’t until analyzing the radar images, however, that the team realized what they had flown over without even realizing it.

The CIRES-led study used ground-penetrating radar to estimate the amount of waste under the ice. The team found that the waste at Camp Century covers about 136 acres, about the size of 100 football fields, and contains an estimated 53,000 gallons of diesel fuel and 63,000 gallons of wastewater.

A team of NASA engineers aboard the Gulfstream III detected something buried under the ice sheet in Northwestern Greenland. NASA scientists didn't know what it was at first, until discovering it was Camp Century,

NASA scientists have located Camp Century, a U.S. military base from the Cold War era, buried deep beneath Greenland’s ice sheet. Built in the 1950s and abandoned in 1967, the base remained hidden under layers of ice for decades.