Although I have already covered the Catacombs in my notes, I thought perhaps it would be wise to append this image to my initial description. The graphic I have attached is the most complete map of the Deep Catacombs to date; while there are still passages that are unmarked and unexplored, this depiction covers the known highlights.
The farthest I have traveled, as a student, is the Hall, an enormous and grand room which once may have been a chapel carved into the limestone. The passages above the Hall are considered safe. They are well-lit, extensively mapped, and maintained regularly, and contain the vast majority of books and supplies that are used by the monks.
Any room below the Dagger is considered to be the Deep Catacombs. These corridors are not maintained, and our knowledge of them comes largely from history books; while we still send expeditions to the Deep Catacombs, it is impossible to traverse them entirely due to their size and complexity. The Deep Catacombs are vast and mysterious, and although I have not been to them myself, I have read much about them.
I have labeled a few of the most interesting parts of the Catacombs on the map and am happy to answer questions about them, or any other part of the passages, to the best of my ability. May Ántou be with you.
Read my previous entry on the Catacombs here.