Sinkhole

09.08.2006
Residents of Novoselovo district in the Krasnoyarsk region have come across a mysterious phenomenon in the field. They discovered several tunnels of unknown origin in an area located some 100 meters away from the highway connecting the cities of Krasnoyarsk and Abakan , in the vicinity of the village of Kurgany, Siberian News Agency reports. There are about 10 holes in the field. Each hole has an entrance to a cave-like hollow place in the earth. Some of the tunnels are big enough for a person of medium height to stand up straight.

http://english.pravda.ru/science/earth/09-08-2006/83834-holes-0/