At age 21, climber Tommy Caldwell pushed his kidnapper off a cliff. Here's what he learned from the experience.

"I figured in that moment that I just killed someone. He fell 20 or 30 feet, bounced off a ledge, and then we just saw him disappear into the blackness."

"Climbing prepared him for high-stress situations... learning to manage his emotions and making quick decisions in high-stress moments helped him during the traumatic kidnapping experience."

Read at Business Insider