The Dwarves created the underground city of Khazad-dûm in J.R.R. Tolkien’s legendarium.
Khazad-dûm, also known as Moria, was the greatest mansion and kingdom of the Dwarves in the Misty Mountains. It was founded by Durin the Deathless, the eldest of the Seven Fathers of the Dwarves, and grew wealthy through mining, especially for the precious metal mithril.
The Dwarves abandoned the city after mining awakened a Balrog beneath the mountains. In The Fellowship of the Ring, the abandoned halls become a dangerous route for the Fellowship. “Moria” is the later Elvish name and means Black Chasm, while Khazad-dûm is the Dwarvish name. This distinction is a frequent source of confusion when readers identify the place only by its better-known name.