http://i.imgur.com/7siUY.jpg
This pic was taken in Centralia, PA, a town destroyed by a coal mine collapsing and catching fire. Apparently the last resident moved out this year. Now it is a ghost town. The fires are still raging beneath the surface. Steam will occasionally come up through the cracks. It's supposed to be very hot inside the cracks (very hot as in like 100+ degrees).
http://en.wikipedia.org/wiki/Centralia,_PA