Waterdeep: Dungeon of the Mad Mage was inspired by The Ruins of Undermountain, Undermountain: The Lost Level, Undermountain: Maddgoth's Castle, Expedition to Undermountain, and Halls of Undermountain.
Waterdeep: Dungeon of the Mad Mage was inspired by The Ruins of Undermountain, Undermountain: The Lost Level, Undermountain: Maddgoth's Castle, Expedition to Undermountain, and Halls of Undermountain.