Aron Ralston is an American outdoorsman – and now motivational speaker – best known for surviving a canyoneering accident in Utah in 2003 during which he amputated his own right forearm with a dull pocketknife in order to free himself from a dislodged boulder, which had him trapped for five days and seven hours (127 hours).

After he freed himself, he had to make his way through the remainder of the canyon, then rappel down a 65-foot (20 m) sheer cliff face to reach safety

The incident is documented in Ralston’s autobiography Between a Rock and a Hard Place and was made into a 2010 film 127 Hours.