It’s touristy but amazing enough that it’s worth dealing with the fat tourists on the tram to see the massive dome in Clara cave. Tres Pueblos is a huge sinkhole that can only be seen from above. Unfortunately even the guides can’t express a large amount of fascination for it in its current presentation.
Apparently there are tours to rappel down the side of some sinkholes (about $60) or kayak down the underground Rio Camuy.