Right inside Hanoi is a historical relic that foreign visitors should not miss when traveling to this city. That is Imperial Citadel of Thang Long.
The central sector of the Imperial Citadel of Thang Long – Hanoi covers an area of 18.395 ha including: the 18 Hoang Dieu Archaeological Site and the remainders in the area of the old Hanoi Citadel such as Hanoi Flag Tower, Doan Mon, Kinh Thien Palace, D67 Building, Doan Mon Gate, Hau Lau Palace, Forbidden City wall and 8 gates built in Nguyen dynasty. This relic complex is located in Ba Dinh district and enclosed by Pha Dinh Phung street to the North, National Assembly Building and Bac Son street to the South ; National Assembly Building, Doc Lap and Hoang Dieu streets to the West; Dien Bien Phu street to the Southeast and Nguyen Tri Phuong street to the East.
In 1009, Ly Cong Uan was enthroned, founded Ly Dynasty. In July 1010, in autumn, the king declared a royal proclamation to move the capital from Hoa Lu in Ninh Binh to Dai La Citadel. As soon as moving capital , Ly Cong Uan hurried to build Thang Long Citadel. The construction was completed in early 1011. The ancient Thang Long Citadel was encircled by three incorporated forts: the outermost fort called La Thanh or Kinh Thanh (Imperial Citadel), which surrounded the citadel and the runned along the flow of 3 rivers: Red river, To Lich river and Kim Nguu river. The Imperial Citadel is the residence of inhabitants. The middle fort was Hoang Thanh (the Royal Citadel), administrative centre and residence of mandarins . The smallest fort was Tu Cam Thanh (The Forbidden Citadel), the house of the King and his royal family. In Tran dynasty, Thang Long Citadel was repaired and many other buildings were constructed. In early Le dynasty, Royal Citadel and Imperial Citadel were enlarged and upgraded. In the period from 1516 to 1788, under the reign of Mac and Le Trung Hung, Imperial Citadel was destroyed many times. In early 1789, king Quang Trung relocated the capital to Phu Xuan, Thang Long only acted as Bac Thanh. In Nguyen reign, the remainders in Imperial Citadel of Thang Long were alternately transferred to Phu Xuan to build a new Imperial Citadel. Kinh Thien Palace and Hau Lau were retained to serve the Nguyen kings when they worked and rested in Bac Thanh.
In 1805, King Gia Long ordered to remove the surrounding wall of ancient Imperial Citadel and build Hanoi Citadel in Vauban style of French architecture in much smaller size. In 1831, in a big administrative reform, king Minh Mang renamed Thang Long into Hanoi province. After successfully occupying Indochina, the French chose Hanoi as a capital of French Indochina Union and Imperial Citadel of Hanoi was destroyed to serve as a military camp for French army. Since the Vietnamese army took the control of the capital city in 1954, this place became headquarters of Ministry of Defense. Therefore, the first historical value of Imperial Citadel of Thang Long-Hanoi was the living historical book of more than 20 centuries of Thang Long-Hanoi lasting from pre-Thang Long period until now.
Imperial Citadel of Thang Long varied a lot in its long history, but the centre, particularly the Forbidden Citadel was almost unchanged. However, interior architectures were rebuilt several times. This is just the answer for question why there are many layers of architectural vestiges and artifacts in the Hoang Dieu Archaeological Site. Those relics have a close relation and connection, creating a complicated general but very rich and attractive, reflecting clearly the relation between urban planning and architectural space, as well as the succession between dynasties in the history of building Imperial Citadel of Thang Long capital. That was prominent unique value of the central sector of the Imperial Citadel of Thang Long. The archaeologists also excavated a large number of ceramics which were used daily by the Kings through different historical periods. These discoveries really opened a new door for researches on ceramics made in Thang Long and ceramics used in Thang Long Citadel through dynasties. They are also the visible evidence for advanced economic and cultural development. In addition, that many bronze coins and ceramics of China, Japan, West Asia….were found here also proved that Thang Long was center of cultural exchanges with other countries in the region and home to quintessence values of humanity.
At 8.30 pm on 31 July 2010, in Brasilia capital of Brazin, the World Heritage Committee UNESCO recognized The central sector of the Imperial Citadel of Thang Long – Hanoi as World Cultural Heritage Site according to 3 outstanding criteria.