The Complex of Hue Monuments is located in and around Hue City in Thua Thien-Hue Province in the geographical centre of Vietnam and with easy access to the sea. Established as the capital of unified Vietnam in 1802 CE, Hue was not only the political but also the cultural and religious centre under the Nguyen Dynasty, the last royal dynasty of Vietnamese history, from 1802 to 1945 CE.
The grounds of the Imperial City are protected by fortified ramparts 2 kilometers by 2 kilometers, and ringed by a moat. The water in the moat is routed from the Huong River (Perfume River) through a series of sluice gates. This enclosure is the Citadel (Kinh thành). Inside the Citadel is the Imperial City (Hoàng thành), with a perimeter wall some 2.5 kilometers in length. Within the Imperial City is the Purple Forbidden City (Tử cấm thành), a term similar to the Forbidden City in Beijing. Access to the innermost enclosure is restricted to the Nguyễn imperial family.
In June 1802 Nguyễn Ánh took control of Vietnam and proclaimed himself Emperor Gia Long. His rule was recognized in 1804. Gia Long consulted with geomancers to look for the best place for a new palace and citadel. After the geomancers had decided on a suitable site in Huế, building began in 1804. Thousands of workers were ordered to produce a wall and moat, 10 kilometers long. Initially the walls were earthen, but later these earthen walls were replaced by stone walls, 2 meters thick.
The structures of the Complex of Hue Monuments are carefully placed within the natural setting of the site and aligned cosmologically with the Five Cardinal Points (centre, west, east, north, south), the Five Elements (earth, metal, wood, water, fire), and the Five Colours (yellow, white, blue, black, red).
Outside the Capital City there are several associated monuments of importance. In the outlying areas were located important ritual sites related to the spiritual life of the dynasty such as the Van Mieu (Temple of Literature), the Dan Nam Giao (Esplanade of Sacrifice to the Heaven and Earth), the Ho Quyen (Royal Area), the Den Voi Re (Temple of the Roaring Elephant), and the Chua Thien Mu (Celestial Lady Pagoda). Further upstream, arranged along the Perfume River were the tombs of the dynasty’s emperors.