Undermountain is a sprawling dungeon complex build beneath the city, which many argue is the deepest dungeon in the world. The main entrance in the city is through a massive hole in the eponymous Yawning Portal Inn, where explorers and adventurers are lowered to the first level of the dungeon in an elevator. The complex was first created by the Melairkyn dwarves thousands of years before the city was founded. Over a thousand years ago, it was cleared of drow and dwarves by a mad wizard named Halaster Blackcloak and his apprentices, who took it over. It is believed that they still dwell in the dungeon to this day. Undermountain also provides another (and much more dangerous) route to Skullport, a city located deep beneat Waterdeep (usually accessed via ship through the River Sargauth under Mount Waterdeep).