Love your articles. One of the few Authors that constantly impress me with new interesting knowledge. Thanks for that. Now as for sinkholes in Germany a whole town (or half don't quite remember) was trashed due to a massive sinkhole which was probably caused due to a coalmine nearby. Don't quote me on that been some time since that happened but Nature is fairly scary and I hate that we keep messing with her it's not gonna do as any good in the end.