Lord Daniel writes:
"It takes but little thought to see that we can classify holes into two categories: natural and anthropogenic. While the study of the influence of natural holes on the history of man in the 12th century could be quite interesting; caves, sinkholes, calderas, and meteoric craters all have their special appeal, as they are, by their very nature, natural and thus lack human input into their creation, I humbly submit that they quite properly fall outside of our general area of interest."

As one who is a Chirurgeon...