Imperial Citadel of Thăng Long, Hanoi

The Imperial Citadel of Thăng Long is a complex of historic imperial buildings located in the centre of Hanoi. It was first constructed in 1011 under the reign of Emperor Lý Thái Tổ of Lý dynasty.

The royal enclosure was first built during the Lý dynasty (1010) and subsequently expanded by the Trần, Lê and finally the Nguyễn dynasty. It remained the seat of the Vietnamese court until 1810, when the Nguyễn dynasty chose to move the capital to Huế. The ruins roughly coincide with the Hanoi Citadel today.

The royal palaces and most of the structures in Thăng Long were in varying states of disrepair by the late 19th century with the upheaval of the French conquest of Hanoi. By the 20th century many of the remaining structures were torn down. Only in the 21st century are the ruin foundations of Thăng Long Imperial City systematically excavated.

In mid-1945 the Citadel was used by the Imperial Japanese Army to imprison over 4000 French colonial soldiers captured during the Japanese coup d'état in French Indochina in March 1945.

The central sector of the imperial citadel was listed in UNESCO's World Heritage Site on July 31, 2010 at its session in Brazil, as "The Central Sector of the Imperial Citadel of Thăng Long – Hanoi".