The cave takes your breath away both because of the beautiful and odd shapes and the shear size. However, you can't help but notice the damage that humans have caused. A lot of the surfaces are covered with soot from the acetylene lamps and candles that were used in the past to light up the cave. Those have been replaced by electric lights, however the electric lights prompt algae growth on the rocks. You really can't win unless the cave is closed to visitors, then the cave wins and we can't be having that.
Tours run every half hour or so and there is a warning before you go in that there are 500 steps down...and 500 back up again. I think a few people on our tour would have done well to heed this sign. The guide gives the tour in Italian but also has tapes in other languages which they play after each spiel. The English tape was a very English sounding lady, quite amusing.
There are a number of experiments run in the cave, mainly to do with the geosciences. One consists of two pendulums which are suspended from the ceiling of the cave and hang to the floor (~ 100 m). These are used to measure very small movements of the Earth's crust and can even pick up the tiny tidal motions of the Earth surface. Very cool.