Fifty years ago, the world was a harsher, more primitive place—at least in terms of adventure sports. Think for a moment about a little route on El Capitan in Yosemite called The Nose. Its slick granite face was difficult for a team of climbers to ascend after weeks of dangerous toil, let alone all-free and in a day. Meanwhile, bicycles of the time didn’t boast suspension forks or disc brakes and surfers couldn’t stay in Northern California waters for longer than a half hour without turning blue. Skiing was still a ballet-like sport best done in stretchy woolens and leather boots, and no one even considered running a marathon, swimming 2.4 miles, and biking 112 miles consecutively while wearing a Speedo.