Graffiti is only one type of damage inconsiderate visitors cause. Pictured are two other examples.
The slide at right shows the result of formation mining. Large pieces of this once- beautiful flowstone drapery have been removed by visitors looking for souvenirs or hoping to make onyx figurines. Just to the right of center, a railroad spike was driven into the flowstone and left to rust. We can assume that the rest of the flowstone mass was broken off and removed by similar means. Even in a cave that is actively developing formations, it can take thousands of years for nature to repair this kind of damage.
Another example, perhaps more distressing, is given at left. This photo shows the decayed remains of an endangered Indiana bat. Vandals dug under a locked, protective fence to gain access to a cave that was closed for bat hibernation, ignoring clear signs at the entrance. The vandals then proceeded to shoot a number of the clustered bats with a B-B gun. One has to wonder at the mentality of someone who would go to such lengths -- risking criminal prosecution -- to accomplish this objective.