Angband

Angband was a mighty fortified citadel originally constructed by Melkor in the earliest days of the world as an outlying fortress to his northern stronghold of Utumno. Melkor built Angband during the Years of the Trees, originally as an outlying fortress and armoury to his great northern citadel at Utumno. It was commanded from its first construction by Sauron, the chief of Melkor's servants. Utumno was destroyed by the Valar, and Melkor imprisoned in Valinor for three ages, but on his return to Middle-earth, he took Angband as the seat of his power, and raised the towers of Thangorodrim above its gates.