1846 wagon train trapped in the Sierra Nevada. Members resorted to cannibalism to survive; only about half made it out alive. The pioneer-era nightmare.
From Wikipedia
The Donner Party, sometimes called the Donner–Reed Party, was a group of American pioneers who migrated to California in a wagon train from the Midwest. Delayed by a multitude of mishaps, they spent the winter of 1846–1847 snowbound in the Sierra Nevada. Some of the migrants resorted to cannibalism to survive, mainly eating the bodies of those who had succumbed to starvation, sickness, or extreme cold, but in one case murdering and eating two Miwok guides.