More of the caves. The place did a VERY good job of keeping the place "just as it was." Our tour guide, a geologist, would walk into a new area, push a button, and LED's would light up the manmade walkway. The lights were on a timer and would shut themselves off after we left the area, so that the heat (which was minimal from the small LED lights) didn't change the normal atmosphere. Any place that you could come into contact with the rock formations had a plexiglass shield around it. It takes thousands of years for them to grow an inch.