Bedlam

In Ultima Online, the dungeon of Bedlam is located directly under the city of Umbra on Malas at 21°08'N 52°22'E.

Description
The dungeon was originally used by the Necromancers of the city as an academy, but after some of the creations went amok, it was abondoned and left to decay. One can enter it, after getting permission, through a secret entrance in an iron maiden. The main prize is the big library, but to enter it, one first has to solve the puzzle of the Master Cohenn. And even if entrance is granted, there still is the problem of a powerful beast guarding the tomes.

Trivia

 * Level two houses a very dangerous champion spawn point; dangerous because the beasts all carry pestilence.
 * In order to enter Bedlam, you first need to start the quest chain Mistaken Identity by talking to Aernya Mistress of Admissions who can be found near the entrance.