Citadel began to build at the beginning of the XIX century. Initially, the Citadel was built from the ground, but in the first decade of the XIX century. Tens of thousands of people worked on the construction of the ramparts built in the style of the French military engineer Vauban. Inside the Citadel is the imperial city - original copy of the Forbidden City of Beijing.

During the war with the United States and the Imperial Citadel, the city has suffered from a hundred buildings have survived only about twenty. In part there is a reconstruction and restoration of buildings, but much is left in ruins.

Gates Ngomon are inside the citadel and have five inputs: central - for the emperor, the two - for royal elephants and two - for the royal servants mandarins. The gate is crowned by a huge watchtower five phoenixes. Here in 1945, the last emperor of the Nguyen Dynasty signed the abdication.

Signal Tower Cat By dominates the southern fortifications of the Citadel. Not far from her, and the gate is Ngan area for parades, in which there are nine bronze cannons - the so-called dynastic gun. They symbolize the four seasons and five elements of ritual.