From the end of 1980s a strange phenomena is happening in some Russian forests. People find strange, deep holes.
They appear in the dense forest, in the places you can’t get on the car or truck to bring any device to drill the ground. There is no any soil that should be taken from such deep holes is found.
On this pictures people go down to one of such holes but it just finishes with nothing. There are no any reasonable ideas on how these holes appear and what they are being used for. Few believe this could be the the work of aliens but there's no proof to support this theory.