Doctor Doom's main headquarters, Castle Doom, had been built on a faultine. Knowing this, Doom built a subterranean Vibration Machine, hidden in the foundations of the castle, that could cause an earthquake to demolish the castle. The seism, while brutal, only affected the castle and its immediate vicinity; and Doom could activate it from a remote control if in the nearby grounds. People in the castle would suffer damage. Doom's purpose was to use it should the castle fall in the wrong hands, and indeed he used it when pretender Prince Rudolfo attempted a coup against Doom. When the castle fell, Rudolfo and his allies -including the alien Faceless One were forced to escape. Immediately after that, Doom started rebuilding.