Haunting image taken by trapped mountaineer before facing choice of cutting own arm off or death

Here is the true story behind the haunting image which inspired Danny Boyle's film 127 hours.

The 2010 drama stars James Franco as an ambitious mountaineer who was forced to make an impossible decision after getting trapped climbing alone in Bluejohn Canyon, Utah.

Watch the trailer below:

127 hours would go on to be a huge success, with Franco earning an Oscar nomination for his portrayal of Aron, a man who (spoiler alert) is forced to amputate his own arm in order to survive.

While the film highlights the lengths humans will go to in order to survive - being both uplifting and terrifying - Aron's situation is one which everyone who is reading this article would dread to ever find themselves in.

Which is all the more chilling when you learn that Aron Ralston is a real person who found himself stuck in a canyon with his right arm lodged behind a boulder.

James Franco as Aron Ralston in 127 Hours (Warner Bros/Searchlight Pictures)

What happened to Aron Ralston: the man who inspired 127 Hours?

Unable to move the rock and with no hope of loved ones being able find his location in time (Ralston had declined to tell anyone where he was going hiking), the 49-year-old was forced to do something most of us would consider unthinkable.

Break all the bones in his right arm and then hack the limb off with a dull pocket knife - an experience which he would surprisingly live to tall the tale.

Prior to the horrifying revelation, Ralston would capture what would go on to be the final image of his right arm, after snapping a photo of himself trapped in the canyon.

Recalling the harrowing experience of cutting himself free from the boulder in an interview with The Guardian, Ralston said: "I'm trying to rip my arm out from the rock, I feel it bend and it stops me – 'That's it! I can use the boulder to break my bones.'"

A photo showing Aron's arm tapped behind the boulder (Simon & Schuster)

After successfully breaking his bone against the rock, his knife was too blunt to cut through bone, Ralston was able to slice through his flesh in around an hour. "As painful as it all was, the momentum of the euphoria was driving it," he added.

After finally freeing himself from a rocky doom, Ralston was able to lower himself to the ground and escape the canyon, eventually being found by a group of Dutch tourists.

He would later write about his experiences in 2004 autobiography Between a Rock and a Hard Place.

You'd think such a harrowing experience would be enough to keep a person away from the wilderness for good, however, Ralston still enjoys heading out into the wilderness.

Only now he probably makes sure somebody is aware of his location.