Moria

Moria, also called Khazad-dûm in the tongue of the Dwarves and Hadhodrond by the Elves, is the greatest and most renowned of the Dwarf-realms of Middle-earth, a vast underground city delved through the heart of the Misty Mountains. Once a place of splendor, wealth, and craft, it became in later ages a haunted and shadow-filled ruin, abandoned to orcs and to a far older terror. Its name Moria means "the Black Pit."

Khazad-dûm was the ancient mansion of Durin's Folk, the eldest of the houses of Dwarves, founded by Durin the Deathless in the depths of time. Its halls were hewn from the rock beneath three mountain peaks, and from its mines came mithril, the rare and precious silver-steel found nowhere else.

Geography

Moria runs beneath the Misty Mountains from the West-gate, near the dark lake of the Hollin Gate where the doors opened with the word "mellon" (friend), to the East-gate, the Dimrill Gate, looking out over the vale of Azanulbizar and the lake of Mirrormere. Within lie great halls, deep mines, the Endless Stair, the bridge of Khazad-dûm spanning a black chasm, and the Chamber of Mazarbul where the Dwarves made their last stand. Far below run the deep places where, the Dwarves dug too greedily and too deep, and woke an ancient evil.

History

Khazad-dûm flourished for thousands of years as the chief realm of Durin's Folk, growing especially rich and powerful through the mining of mithril and through friendship and trade with the Elves of Eregion nearby. Its downfall came when the Dwarves, delving for mithril, awoke a Balrog of Morgoth, a demon of fire and shadow from the Elder Days, that had lain hidden in the deep. The Balrog, named Durin's Bane, slew the king and drove the Dwarves out, and Khazad-dûm became Moria, the Black Pit, abandoned and dreadful.

Long after, Balin, a companion of Bilbo in earlier days, led an ill-fated colony to retake Moria, but the venture ended in slaughter, and the Dwarves were destroyed by the orcs that infested the mines.

In the story

The Fellowship of the Ring, unable to cross the mountains by the pass of Caradhras, takes the dark road through Moria. There they read the record of Balin's doomed colony in the Chamber of Mazarbul and are beset by orcs and a cave-troll. At the bridge of Khazad-dûm, Gandalf confronts Durin's Bane, the Balrog, and casts it down, but is dragged into the abyss with it, falling, as it seems, to his death, before his return transformed as Gandalf the White.