It was 50 years ago on February 2, 1959, when evil aliens flying over Russia's Ural Mountains in a UFO happened upon a tent and fired their death ray at it, causing the deaths of the nine humans inside. Well, maybe the mysterious event known as the Dyatlov Pass Accident didn't happen that way, but that was the personal opinion of the lead investigator, Lev Ivanov.

The weird event began when a group of 9 students --- seven men and two women --- of Ural Polytechnical Institute embarked on a hiking and cross-country skiing trek across the northern Ural Mountains. Their planned route was rated most difficult, but they were all veteran members of a sports club and experienced in mountain expeditions. They traveled by train and truck to get to Vizhai, the region's northernmost settlement, and then went into the wild on skis and foot, depending on the terrain.

A snowstorm on the fifth day caused them to veer off track, so they decided to make camp at the foot of "Kholat Syakhl", a mountain so-named by the indigenous Mansi aborgines, meaning " Mountaon of the death". Their diary entries didn't indicate anything unusual and the adventurers even posed for photos and took snapshots of the nearby scenery before having dinner and going to sleep. Then something happened. The official investigation lasted three months, but only concluded that the nine trekkers died due to an "unknown compelling force".

Evidence at their last camp told some of the story. In the middle of the night, all nine fled the tent so suddenly that the bodies were found lying in the snow in various states of dress --- without coats or blankets, in socks, with one boot on, barefoot, etc. Rather than untie the tent flaps they actually tore a gaping hole in the tent's side to flee out of. Despite their experience in the wild, they fled half-dressed into -30 degree C weather and quickly died.

The post-mortem examinations indicated that five of the victims simply died of hypothermia. One of these five, however, had a slight crack in his skull. One the other four victims. one had a massive skull fracture, two had several broken ribs, and one of the women was found missing her tongue. Huh? It gets weirder.

After the funerals, the relatives of the dead complained that their skin was deeply tanned. Also, it's possible the victims were blinded. In the few hours that some of the victims survived, they collected damp, living branched pulled from trees while there was plenty of dry deadwood lying around.

The victims' clothing was highly radiation was identified. Also the severity of the chest and skull trauma sustained by three of the victims was owing to extreme force comparable to a car accident, and not possible from physical attack. The lack of prints in the snow ruled out a visit by the Mansis oe wild animals.

Theories? The investigation was unable to postulate any, and after three months the case was officially closed due to the "absence of a guilty party." The case files were classified and were not made public until the 1990s, after the dissolution of the Soviet Union. However, the files are still missing important parts, such as reports related to the victims' internal organs.

Conspiracy theories abound, with a leading one suggesting that the Soviet military had developed a Cold War era secret weapon and, by accident or design, fired it at the victims. There is still wildspread interest in the case, with two novels, investigative books and a documentary film devoted, but the mystery of Dyatlov Pass remains unsolved.