Something happened on Dead Mountain in 1959, and no one can explain it. Nine experienced hikers fled their tent in the dead of night, leaving behind their belongings and walking barefoot into sub-zero temperatures. Found scattered across the snow with strange injuries and no clear cause of death, their story remains one of history’s most chilling unsolved mysteries. From avalanches and infrasound to UFOs and Yetis, we’re unpacking the evidence and the wildest theories behind the Dyatlov Pass Incident.