seen from Brazil
seen from United States
seen from Yemen
seen from United States
seen from Belgium
seen from Switzerland
seen from United States
seen from United States
seen from Germany
seen from Malaysia
seen from T1
seen from Mexico
seen from Spain
seen from China
seen from Austria
seen from United States
seen from United States
seen from France
seen from T1
seen from United Kingdom
Many 1st level characters explored The Haunted Keep, found in Moldvay's 1981 D&D Basic Rules in the "DM Instructions" section. Moldvay walked a new DM through the process of drawing a map and stocking a dungeon, leaving the west tower and lower catacombs for the DM to create. Erol Otus also drew the keep in cross-section, and other writers have published their versions of the expanded areas.
The Haunted Keep appears in Moldvay's 1981 D&D Basic Rulebook as a partial sample dungeon. It's a good starting point for designing your own larger multi-level dungeon, but there are several finished versions out there that are ready to play.
DF23: The Haunted Keep is 35 page PDF available free on the Dragonsfoot publications page. I might run it after my current campaign finishes B1 and B2.
(Dragonsfoot bills itself as "the home of 1st Edition AD&D" but there is also a wealth of material there for OD&D, 2nd Ed, or any OSR clone you want to play. If you haven't been there before, be prepared to lose a lot of time when you click the link.)
A different adventure with the same inspiration that I haven't read yet is Shadow of the Haunted Keep, available from DriveThru RPG/RPGnow.
