While scouting for game in Grand River in 1823, Hugh Glass ran into a grizzly-bear mom who attacked him to defend her two cubs.

Unable to reach his rifle as they wrestled on the ground, Glass was able to escape from her death grip and stab her with his knife while she shredded his face, chest, arm, and back with her claws. His wounds were so gruesome that his fellow trappers simply placed a bear hide over him as a funeral shroud and left him for dead so they could get out of the hostile territory and away from the Native Americans who had recently killed half of their crew. With pretty much anyone else, the whole horrendous story would have ended there.

But not Hugh Glass. When Glass eventually regained consciousness, he set his own leg, wrapped himself in his bear hide shroud, and started crawling along the banks of the Cheyenne River.

During the insane trek across country that followed, he prevented gangrene from infecting his wounded back by lying on a rotting log and allowing maggots to eat his dead flesh, sustained himself by killing and eating rattlesnakes, and crawled overland for six weeks until he reached civilization — which was really surprised and impressed to see him alive.