Roger Bannister failed to win a medal at the Helsinki Olympics and returned to England a failure. To compensate, he set about summiting his sport’s Everest– he would run under four minutes for the mile.

Despite taking classes and working shifts at a hospital to earn his doctorate degree, Bannister made time every day to take a train to the track and run ten 400 meter repeats with about a minute’s rest in between.

(At night, he’d conduct the first-ever studies on oxygen intake by hooking himself up to a Darth Vader mask and running on a wooden treadmill until he collapsed, but he never noted that in his training log)

Eighteen months later, he ran a mile in less than four minutes and became the most legendary figure in the sport’s history. All in between shifts at a hospital.