abandonedography:

Mir Mine is a former open pit diamond mine, now inactive, located in Mirny, Eastern Siberia, Russia. The mine is 525 meters (1,722 ft) deep and has a diameter of 1,200 m (3,900 ft), and is the second largest excavated hole in the world, after Bingham Canyon Mine. The airspace above the mine is closed for helicopters because of incidents in which they were sucked in by the downward air flow. (via)

(via 5leepyhead)