Moria

In the fictional history of the world by J. R. R. Tolkien, Moria, also named Khazad-dûm, is an ancient subterranean complex in Middle-earth, comprising a vast labyrinthine network of tunnels, chambers, mines, and halls under the Misty Mountains, with doors on both the western and the eastern sides of the mountain range. Moria is introduced in Tolkien's novel The Hobbit, and is a major scene of action in The Lord of the Rings.

In much of Middle-earth's history, Moria was the greatest city of the Dwarves. The city's wealth was founded on its mines, which produced mithril, a fictional metal of great beauty and strength, suitable for armour. The Dwarves dug too greedily and too deep for mithril, and disturbed a demon of great power: a Balrog, which destroyed their kingdom. By the end of the Third Age, Moria had long been abandoned by the Dwarves, and was a place of evil repute. It was dark, in dangerous disrepair, and in its labyrinths lurked Orcs and the Balrog.