Undermountain

The expansive, deadly and hidden world beneath Waterdeep, originally the Undermountain was carved thousands of years ago by Dwarves, the Melairkyn, delving for precious Mithril. Their mines were overrun by many foul things, claiming control over much of the territory, many levels changing ownership several times between the rapidly declining dwarves, Duergar, Drow, and other evils under the world.
There are several ways to enter the Undermountain, the vast majority sealed and guarded by the Lords of Waterdeep, but the most famous entrance lies in what is now The Yawning Portal tavern, where Durnan charges a fee for adventuring parties to test themselves.

Type

Underground / Subterranean