You probably can't even begin to fathom making the decision to amputate your own arm with a dull knife. But on May 1, 2003, Aron Ralston was left with no other choice. An 800-pound (362.8 kilogram) boulder fell on his arm and trapped him in a Utah canyon wall.
After lying pinned to the canyon for five days, Ralston, running out of food and water, thought chances of being found were slim. He leveraged the boulder to make his bones snap, and he then used his pocket knife to cut away his muscles and tendon. Amazingly, he rappelled down a 65 foot wall and walked until hikers found him.
Ralston is truly a testament of bravery and survival. The amputee has since climbed all of Colorado's peaks and is a motivational speaker.