People can not deceive nature. Sooner or later it will conquer back all the territories that belonged to her in the past.
Many million years ago the territory of the present Perm region was occupied by the Perm Sea. The sea dried out later leaving the unique Verchnekamsk potassium deposit instead. First saltworks here were observed in 1430. In Soviet times mineral production was expanded considerably leading to the union of several villages into one town. 4 mines surround the town.
In 1986 one mine far from the town was flooded and a sink was formed on its surface.The slope mine under the town was slowly filled with salt brine making the surface subside. The buildings are removed as life in them is dangerous due to a high risk of sink formation. What you see in the picture is the first sink.
First sink after a while.
Second sink was initially small as well.
It increased later.