The Pokemon Mansion is an abandoned mansion on Cinnabar Island filled with wild Pokémon. It housed the key needed to access the Cinnabar Island gym, as well as various reports on Mewtwo's birth and subsequent escape. Burglar Simon also resided at the mansion, and proved to be a frustrating object for Red and Abe.
The mansion is filled with connected locking doors which are activated by switches hidden in statues. Activating a switch will unlock one set of doors whilst locking another.
The mansion along with most of Cinnabar Island was destroyed when the volcano erupted.