Khazad-Dûm is an ancient underground city and the former stronghold of the Dwarves in Middle-earth, created by the Dwarven king Durin. It is renowned for its vast halls, intricate architecture, and rich deposits of mithril, a precious metal. Located beneath the Misty Mountains, Khazad-Dûm was once a thriving center of trade and craftsmanship. However, it fell into darkness after the awakening of the Balrog, a powerful creature, leading to its abandonment. The city is also known as Moria in later times, reflecting its tragic history and the dangers that lurked within its depths.