Børge Ousland
Norway
Norwegian explorer Borge Ousland completed a solo, unsupported trek across the North Pole on foot in 52 days in March 2001. He endured temperatures as low as -50 degrees C, constantly shifting sea ice, and the threat of polar bears while covering roughly 1,800 km. Ousland is also the first person to have crossed both the Antarctic and the Arctic solo. Climate-change-driven ice loss is making Arctic crossings increasingly dangerous, rendering this record ever harder to replicate.