"If we were to talk about most natural dungeons in existence or that have existed in the past, then we are talking about dungeons before the second and third cataclysm.
As is widely known the dungeon mutation phenomena started after the second cataclysm but what is mostly overlooked is that the phenomena didn't go out of control until the third cataclysm, commonly known as the Age of Dread."
At this point one of the students in the front seats raised her hand and after getting a nod from the professor, she asked,
"Then, why are there so few natural dungeons anymore?"
"A fine question. It is well known that finding a dungeon is very rare. In the time before and even after the second cataclysm it was very hard to encounter a dungeon and all natural dungeons can be close permanently so most any dungeons found were dealt with in a very simple and final manner."
Another student raised her hand.
"Why don't we just do the same to unnatural dungeons and be done with it?"