Joshua Foer is a guest blogger on Boing Boing. Joshua is a freelance science journalist and the co-founder of the Atlas Obscura: A Compendium of the World's Wonders, Curiosities, and Esoterica, with Dylan Thuras.
Speaking of giant holes in the ground, let me pass along one more that happens to be one of today's featured places on the Atlas Obscura home page. The Mirny diamond mine in Siberia is the biggest man-made ditch in the world:
The largest man-made hole in the world is a diamond mine located on the outskirts of Mirny, a small town in eastern Siberia. Begun in 1955, the pit is now 525 meters deep and 1.25 kilometers across. The massive 20-foot tall rock-hauling trucks that service the mine travel along a road that spirals down from the lip of the hole to its basin. Round-trip travel time: two hours. Airspace above the mine is off-limits to helicopters, after "a few accidents when they were 'sucked in' by downward air flow…"