Built in 1804 on a site chosen by the Emperor Gia Long's geomancers, the imperial city was originally made of earth and later strengthened with brick. It covers a total area of over 500ha including 3 sets of wall. Outside is the Citadel surrounded by the 2m-thick and 10k-long walls. Inside the Citadel is the Imperial Enclosure with a perimeter of about 2.5 km. At the very center of the Imperial Enclosure is the Purple Forbidden city consisting of a network of palaces, gates, courtyard and gardens.
Recognized as a World Cultural Heritage Site by UNESCO, the Imperial City has become the most important historical and cultural monument of Vietnam.