There was a layer of crystalized salt over the sand. There were also huge crystal/rock formations that would creak once in a while. So I didn't get to close to the edge of the cave. The salt sometimes looked like a frozen over lake with snow and sand on top. It was pretty interesting, I have never seen anything like it before. There were also other caves with more crystals in them, but I didn't get to those. My butt was very sore by this point in the trip, and riding down the road with mounds of sand and salt was not the most pleasant thing in the world....but it was worth it.