Dungeons

Over the course of a hundred or more centuries, the Underdark deep caverns and vaults have been expanded tremendously by the delving of various deep races. Thus, the term dungeon when applied to the Underdark means a structure excavated from the surrounding rock by intelligent creatures. For example, a great Duergar city delved into the wall of a vault might be considered a large dungeon, with halls and passageways extending for miles from its entranceways. Dungeon complexes often serve to link two natural features such as two or more vaults close to each other with a system of artificial caves that vastly extends the scope of a natural cave system.

Dungeons come in two varieties—abandoned and occupied. Since they are not sources of food or water in and of themselves, empty dungeons do not necessarily attract Underdark settlers. However, dungeons are often supremely well suited for defense, and a dungeon that happens to be near a rich area such as a living cave is almost certain to be occupied by something, even if the original builders are long gone.