The heart of Hue. The Citadel is a massive walled fortress built by Emperor Gia Long in 1805, surrounded by a wide moat and 2.5 kilometres of walls. Inside lies the Imperial Enclosure, where the emperor conducted official business, and within that the Forbidden Purple City — once reserved for the emperor alone. The complex covers 520 hectares and originally contained over fifty royal buildings, palaces, temples, libraries, and pavilions.
Much was destroyed during the Tet Offensive in 1968, but significant structures survive. The Ngo Mon Gate — the main southern entrance — is where the last Nguyen emperor, Bao Dai, abdicated in 1945, on the same balcony where his predecessors had reviewed royal ceremonies for over a century. Thai Hoa Palace, the principal ceremonial hall, has been restored and gives a sense of the original scale and decoration. The Nine Dynastic Urns in the Hien Lam Pavilion, cast between 1835 and 1837, are engraved with landscapes, animals, and historical scenes covering the entire surface.
Allow at least three hours for a thorough visit. Entry tickets (which also cover the Hue Museum of Royal Fine Arts) are sold at the main Ngo Mon Gate on 23 Thang 8 Street. Hiring a guide at the entrance is worthwhile — the layout is confusing and the history dense.