German quarries, pits and mines

German inland diving is built on industrial leftovers, and the two kinds here are quite different.

Flooded quarries and pits. The Kreidesee at Hemmoor is the great one: chalk was dug there from 1862 to 1976 to feed the cement works next door, and when the pumps stopped the pit filled with groundwater by 1982. It is the third-deepest body of water in northern Germany and there is a great deal in it, from the rubble of the demolished cement factory to a sunken Piper PA-28 that once belonged to the astronaut Alan Shepard. It is also a place people die: cold, deep, and easy to get to.

Slate mines. Nuttlar and Stiefelgrube Christine are not caves. They are worked-out slate mines in the Sauerland and the Upland whose galleries flooded when pumping stopped, and they are dived on fixed guide lines through square-cut, man-made chambers with the tool marks still on the walls. No karst, no system, no natural passage — which is why the system field is blank for both.