Dungeon of the Mad Mage
Welcome to the Undermountain
The largest, deepest, most sprawling dungeon in all of the Forgotten Realms lies beneath the city of Waterdeep and is home to a multitude of dark denizens seeking to devour any foolish adventurers who dare to roam its ancient halls. The Undermountain is a vast series of uncounted interconnected dungeon levels, each deeper than the last, is a testament to the madness of its creator, the mage Halaster Blackcloak.
The only known entrance to the Undermountain is The Yawning Portal, a famous inn and tavern whose common room is dominated by a massive well that descends deep into first layer of the dungeon.The proprietor of the inn, the famed adventurer Durnan who was the first adventurer to return from Undermountain alive, will lower adventurers into the well via a simple winch and rope-and-pulley at the price of a single piece of gold. On rare occasions, adventurers will return via the same mechanism at the same price.