Date of sighting: May 2015
Location of sighting: Ural Mountains, Russia

These holes are appearing all  over the Ural Mountains and all they have are some good guesses, but scientists are still baffled by the exact cause. I do believe that a UFO that is being transported below the ground could cause such a thing, however it is unique and probably only caused by one particular species. The area seems to have many holes so its possible an active alien base is below the Urals. SCW

RT News states:
Subterranean Soviet missile stations – or tunnels to the center of the earth? A whole host of theories have emerged after a large hole appeared near Russia’s Urals mountains. An emergency situation committee has yet to say what caused it, or how they’re responding. Meanwhile mysterious sinkholes have also appeared elsewhere in the region.