Recently there was long thread about the BCA. I can now post possible answers to some of the questions, such as "Why is the BCA still raising membership prices when there is a significant amount still left in its coffers?"
Caves are formed only a couple of ways.
Corrosion.
Erosion.
Torodsion.
The last of these is from back in the day when dynamite was at the local hardware store and Torode was famous for carrying a few sticks caving. Just in case.