In the Kuzovatovsky region of Russia, a deep hole has been created in the field between the villages of Studenets and Nikolskoye. Judging by the pictures, the hole reaches a depth of several tens of meters. According to experts, this is a frequent phenomenon, the so-called karst sinkhole. These are created in various ways. If the roof of an underground cavity (BC. cave) collapse, a sinkhole will appear on the surface.