The city of Huế was the seat of Nguyen Dynasty emperors and the national capital from 1802 to 1945. A major attraction is its vast, 19th-century Äại Nội Citadel, surrounded by a moat and thick stone walls. It encompasses the Imperial City, with palaces and shrines; the Forbidden Purple City (Tử cấm th&agrave;nh), once the emperor&rsquo;s home; and a replica of the Royal Theater.