 After the end of the First Age the power and wealth of Khazad-dûm was much increased; for it was enriched by many people and much lore and craft when the ancient cities of Nogrod and Belegost in the Blue mountains were ruined in the breaking of Thangorodrim.Its wealth was also enriched with the discovery of "mithril", a magical, extremely valuable, and nearly indestructible metal found only in its mines.During this Age, the Dwarves continued to trade with neighbouring Men and the Elves of Eregion.