The picture below is of a cave a few miles from where I live. Its name is "Cathole". We used to use it for crevasse rescue practice, much to the annoyance of a local warden. We also spent quite a few nights in the cave. It has been discovered, only recently, that there is a prehostoric cave painting at the back of the cave. Possibly the oldest bit of art in the whole of Northern Europe... and I failed to spot it! Anway, the back of the cave now has a barrier preventing people going back there. As soon as it was publicised that the cave had a painting in it, some lunatic went there and attempted to destroy it...!