Gravenhollow

Gravenhollow was a legendary library located somewhere in the Underdark. Its location constantly shifted throughout the plane by means unknown. Three Librarians tended to the archives - Ulthar, Keeper of the Past, Urmas, Keeper of the Present, and Ustova, Keeper of the Future.

Visitors to Gravenhollow were lodged at the Gravenhollow Lodge, whose reasonably-priced accommodations supernaturally attuned themselves to the every whim of the business traveler.