Take a look at the beta version of dw.com. We're not done yet! Your opinion can help us make it better.
As pockmarked as Swiss cheese - that's what it looks like under the surface of the Ruhr region. It was once the center of German coal mining; now its residents are struggling with the long-term effects. To prevent the old mineshafts from filling with water and collapsing, they have to be kept pumped out. That's expensive, and it's likely those measures will be needed forever.