People are discovering mysterious, ultra deep holes in Russian forests. They appear in the dense forest where there is no easy access for a car, truck, heavy digging equipment, or even people. Plus, there’s no soil nearby that should be taken from such deep hole to be found. Continue reading for a video and more information.

According to Slightly Warped, “When people are brave enough to venture into the holes, they find that they end abruptly in the darkness. There are no any reasonable ideas on how these holes appear and what they are being used for. No one knows who or what is digging these holes or why.