Sir Ranulph Fiennes had a heart attack and a double bypass. Four months later, at 59, he ran seven marathons in seven days on seven continents, finishing the lot in roughly 26 hours of running. He has also sawed off his own frostbitten fingers with a fretsaw in his garden shed, discovered the lost city of Ubar, and summited Everest at 65. Guinness calls him the greatest living explorer.
