In 1823, frontiersman Hugh Glass was mauled by a grizzly bear during a fur-trapping expedition in present-day South Dakota. He was left with a broken leg, exposed ribs, and festering wounds that convinced his companions he would soon die. After they abandoned him, he regained consciousness, set his own broken leg as best he could, and allowed maggots to eat the dead flesh in his wounds to stave off gangrene.
With no weapons and almost no supplies, he spent about six weeks crawling and hobbling toward the nearest settlement, living mainly on roots, berries, and whatever small animals he could catch along the way. Against all odds, he eventually reached civilization alive.