54 years ago this month, the northern part of the Urals played host to one of the most fascinating unsolved mysteries in the modern age.
On the surface, what's become known as the Dyatlov Pass incident seems fairly explicable: Of a party of ten skiiers, nine perished in the middle of a high-difficulty trek in conditions that reached -30 degrees Celsius. But the details, which are mostly based on diaries of those involved as well as records from Soviet investigators, are chilling: On the night of February 2, 1959, members of the party apparently ripped their tent open from the inside, and wandered into the tundra wearing nothing but what they wore to bed.
An interesting and weird story, but not really what I'd classify as "the strangest unsolved mystery of the last century." Maybe "the strangest unsolved mystery of the Urals in the last century", though.