Climbers Tommy Caldwell and Kevin Jorgeson recently completed the first ever free ascent of El Capitan’s Dawn Wall. This means they climbed, for a total of 19 days, using ropes only to stop a fall, not to aid the climb. Here, Caldwell climbs at night. Hands are less sweaty and climbing shoes less stretchy at night, which helps. The Dawn Wall is "considered the longest, hardest free climb in the world," according to the story in Outside Magazine.