Sir Ranulph Fiennes is a British adventurer whom the Guinness Book of World Records once described as “the world’s greatest living explorer.” Fiennes undertook numerous expeditions, including many in the Arctic and Antarctic, and he was the first person to reach both the North and South Poles. In 1990, he set the world record for unsupported northerly polar travel, and in 1993 he became the first person to cross the continent of Antarctica on foot, completing the longest unsupported polar journey in history. But all that time in frigid temperatures took its toll on Fiennes when he sustained severe frostbite to the tips of his fingers on his left hand, which he later amputated himself. Still, this didn’t slow him down. In 2009, at the age of 65, Fiennes successfully reached the summit of Mount Everest, becoming the oldest British person to ever climb the world’s highest mountain. In the video below, Fiennes — who incidentally, is also a third cousin to actors Ralph and Joseph Fiennes — describes his travels.