D&D 3.0: Tales from Mystara
Mount Umbaroa is an active volcano located on Aloysius Island of the Archipelago of Ierendi. There is also an ancient complex of unknown origin, guarded by powerful fire and earth elementals built into Mount Umbaroa. Many have tried to explore it and died; the Cabal of the Volcano are known to have mounted an expedition which cared off some ancient artifacts of unknown origin from it, but insistent rumor asserts they were unable to bypass the more powerful inner guardians.
The place is rumored to be habitat of Harpies .