From the World Heritage inscription for the Complex of Hué Monuments:
The Complex of Hue Monuments is located in and around Hue City in Thua Thien-Hue Province in the geographical center 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 center under the Nguyen Dynasty, the last royal dynasty of Vietnamese history, from 1802 to 1945 CE.
The plan of the new capital is in accordance with an ancient oriental philosophy and respected the physical conditions of the site.
The Ngu Binh Mountain (known as the Royal Screen) and the Perfume River, which runs through the city, give this unique feudal capital an entire setting of great natural beauty as well defining its symbolic importance. The site was chosen for a combination of natural features – hills representing a protective screen in front of the monuments or taking the role of “a blue dragon” to the left and “a white tiger” to the right – which shielded the main entrance and prevented the entry of malevolent spirits. Within this landscape, the main features of the city are laid out.
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).
The central structure is the Hue Citadel area which was the administrative center of southern Viet Nam during the 17th and 18th centuries CE. Within the Hue Citadel were located not only administrative and military functions of the Empire but also the Imperial Residence, the Hoang Thanh (Imperial City), the Tu Cam Thanh (Forbidden Purple City) and related royal palaces.
Tran Binh Dai, an additional defensive work in the north-east corner of the Capital City, was designed to control movement on the river. Another fortress, Tran Hai Thanh, was constructed a little later to protect the capital against assault from the sea.
Hue is analogous to other Asian cities such as Kyoto, Gyeongju, and Nanjing in that it is a former imperial city. Unlike the other cities, the history doesn’t date back nearly as far. The current structures only date back to the early 19th century.
There actual city of Hue is pretty large; almost one million people. The history part of the city consists of the walled outer city and the walled inner city, which contains the royal residences. Most of the royal buildings are undergoing renovation/reconstruction and there currently isn’t much to see.
In addition to the walled city, the Thien Mu Pagoda (shown above) is also part of the World Heritage site and is located on the river several kilometers out of the city. You can easily get there via bicycle rickshaw.
View the complete list of UNESCO World Heritage Sites in Vietnam.
View the list of all of the UNESCO World Heritage sites I have visited on my travels.