Hue has chosen to be the capital city of the Southern Kingdom by all Nguyen Lords and officially became the capital under Tay Son'reign. For approximately 400 years, Hue has become a great landscape and architectural site. Hue' royal complex has been officially recognized by the UNESCO as a World Heritage Site.

Kinh Thanh Hue (Hue Capital Citadel):

This construction stared in 1805 under the reign of Emperor Gia Long and completed in 1832 under the reign of Emperor Ming Mang. Under Nguyen' reign, Kings have ordered to build ramparts, palaces and constructional works of royal. Over 200 years to now, it is still original with nearly 140 small and large constructions.

The Citadel, square in shape and almost 10 km in circumference, 6 m high, 21 m thick and 10 entrances. On the top of the walls that surround it, 24 bastions are established for defensive purposes. Besides, the Citadel has an ancillary gate connecting the Tran Binh Bastion called the Thai Binh Mon (Peace Gate).

Hoang Thanh (Royal Citadel):

The Imperial City is located in the centre of the Citadel where established highest offices of Viet Nam's feudalism and sanctums honouring the cult of decreased Emperors. The Citadel, also has a nearly square form, with more than 600m long for each side, built of brick 4m high, 1m thick, around which is ditched a system of protection trench. Access to the Imperial City can be made by four entrance gates. Noon Gate is only used for the King. Royal Palace consists of more 100 beautiful constructional works divided many sectors.

• From the Ngo Mon to the Thai Hoa Palace: This is the place for setting up various grand ceremonies.
• Sector for worship shrines of the King of the Nguyen dynasty: Trieu Mieu, Thai Mieu, Hung Mieu, The Mieu and Phung Tien place.
• Sector for internal affairs office: Storehouse for precious objects, workshop for manufacturing various useful articles.
• Sectors for the Kham Van palace and the Co Ha garden: place where the princes are studying or enjoying.

Tu Cam Thanh (Forbidden citadel):

Located inside the Imperial City, behind the Throne Palace, the Forbidden Purple City is reserved for Emperor and his family. Constructed early in Emperor Gia Long'reign in 1804 with brick walls 3.72m high, 0,72 m thick, about 1,230 m in circumference. Its front and back sides are 324 m each while either left and right side is more than 290 m including 50 architectural constructions of different sizes and 7 gates for facilities of entrance and exit. Dai Cung Mon (the Great Place Gate) is in the front side for Kings. Can Chanh Palace (the place for every day working of Emperors). Can Thanh (Emperor's Private Palace), Khon Thai Residence (Queen's Private Apartment) reserved for the Queen. Duyet Thi Duong house (Royal Theatre), Thuong Thien (the kitchen for the King' food), Thai Binh Lau (King's reading room)... Besides, Hue is also famous for royal tombs and temples of Nguyen Kings. Seven tombs with different aspect are not not only a wonderful arch but also combining beautiful, imposing nature and poetic of Hue.