Nine Soviet hikers died on a Ural mountain pass in 1959 under circumstances so strange that the Russian state reopened the case in 2019. Tents cut from the inside, fatal injuries with no external wounds.
The Dyatlov Pass incident was an event in which nine Soviet ski hikers died in the northern part of the Ural Mountains ridge in the Russian SFSR of the Soviet Union on 1 or 2 February 1959 under undetermined circumstances. The experienced trekking group from the Ural Polytechnical Institute, led by Igor Dyatlov, went on a hike of the highest difficulty level at that time, and had established a camp on the eastern slopes of Kholat Syakhl mountain. Overnight, the group cut their way out of their tent with knives and fled the campsite, inadequately dressed for the heavy snowfall, strong winds and extreme cold temperatures as low as −40 °C (−40 °F).