Landmark Asia
Imperial Citadel of Thang Long
The Imperial Citadel of Thang Long is in Hanoi, Vietnam. Rulers lived and worked here for hundreds and hundreds of years!
The Imperial Citadel of Thang Long is in the heart of Hanoi, the capital of Vietnam. It was built in the 11th century by the Ly dynasty, on the remains of a 7th-century fortress. For almost 13 centuries it was a center of power. Its gates, old palace foundations and an archaeological site are a UNESCO World Heritage Site.
The Central Sector of the Imperial Citadel of Thang Long, in the heart of Hanoi, was built in the 11th century by the Ly dynasty on the remains of a 7th-century Chinese fortress, on land drained from the Red River Delta. UNESCO calls it a seat of regional political power for almost thirteen centuries, shaped by influences from China in the north and the Kingdom of Champa in the south.
Photo: Emmanuel BRUNNER (Manu25), CC BY-SA 3.0, via Wikimedia Commons
Discover the Imperial Citadel
The Imperial Citadel is in Hanoi, the capital city of Vietnam.
A citadel is a strong walled place where rulers lived and worked.
The Imperial Citadel of Thang Long lies in the heart of Hanoi, the capital of Vietnam. It was built on drained land taken from the delta of the Red River.
The World Heritage Site is its central sector, which UNESCO calls the most important and best-preserved part of the old citadel. It covers about 18 hectares.
UNESCO describes the Central Sector of the Imperial Citadel of Thang Long - Hanoi as the most important and best-preserved part of the ancient citadel, located in the heart of Vietnam's capital, on drained land reclaimed from the Red River Delta.
The property (18.395 ha) follows the old north-south axis of the Forbidden City and includes the 18 Hoang Dieu Archaeological Site just to the west, where the oldest remains have been found.
- Where
- Hanoi, Vietnam
- Built
- 11th century (Ly dynasty)
- Area
- 18.395 ha
- World Heritage Site
- 2010
Nearly 13 centuries of rulers
The citadel was built about a thousand years ago.
Kings and rulers lived and worked here for a very long time.
UNESCO says the Ly dynasty built the citadel in the 11th century, on the remains of a Chinese fortress from the 7th century. It marked the independence of Dai Viet, the Vietnamese kingdom of the time.
For almost 13 centuries, it stayed a center of power. Its walls were rebuilt in 1805, after the capital had moved to Hue, further south.
The Thang Long Imperial Citadel was built in the 11th century by the Vietnamese Ly dynasty, marking the independence of Dai Viet, on the remains of a 7th-century Chinese fortress. UNESCO calls it the center of regional political power for almost thirteen centuries without interruption.
ICOMOS records that the citadel reached its greatest size in the 16th-17th centuries, that its fortifications were rebuilt in 1805 on a European model, and that the capital moved to Hue under the Nguyen dynasty. Many buildings were rebuilt in a European, mostly Neoclassical, style in the colonial period.
Gates, towers and palace foundations
The citadel has old gates and a brick tower 33 meters tall.
The old palace is gone, but its stone steps are still there!
The main buildings line up along a north-south path. In the south stands the Flag Tower, built in 1805, 33.4 meters high. Next comes Doan Mon Gate, once the formal way into the Forbidden City, with parts from the 1400s.
Kinh Thien Palace was built in the early 1400s. It was demolished in the colonial period, but its foundations and two flights of stone steps are still there.
ICOMOS lists the monuments along the north-south axis: the Flag Tower (Ky Dai, 1805), a stepped brick tower 33.4 m high with a spiral staircase; Doan Mon Gate, the formal entrance to the Forbidden City, with 15th-century sections and 19th-century restorations, topped by a two-story pavilion with a double, upturned roof; and the foundations of Kinh Thien Palace.
Kinh Thien Palace, from the early 15th century, stood on foundations of 11th- and 12th-century palaces; it was demolished and rebuilt in the colonial period. Two flights of steps with carved stone railings survive.
Digging up 13 centuries
People dug carefully into the ground next to the citadel.
They found the remains of very old palaces, pots and roof decorations!
In 2002, digging began at a site called 18 Hoang Dieu, next to the old Forbidden City, during building work for a new National Assembly building. Archaeologists found remains from about 13 centuries of history, one layer on top of another.
They uncovered palace foundations, a drainage system, pottery and many roof decorations.
The 18 Hoang Dieu Archaeological Site, excavated from 2002 during building work for a new National Assembly, revealed a chronology of around thirteen centuries (8th-19th centuries), with remains of palaces and residences, a drainage network covering the whole site, ceramics and many architectural pieces.
UNESCO lists the property for criteria (ii), (iii) and (vi): it shows influences from China and the Kingdom of Champa meeting in the lower Red River Valley, and the long cultural tradition of the Viet peoples of the delta.
- Flag Tower
- 1805, 33.4 m
- Excavations at 18 Hoang Dieu
- from 2002
- Northern gate (Bac Mon)
- rebuilt 1805
- UNESCO criteria
- (ii)(iii)(vi)
A pavilion at nightfall
In this photo, an old building glows with golden light. The sky is dark blue.
Its curved roofs point up at the corners.
This photo was taken on 9 March 2013, at nightfall. A two-story building in the citadel is lit up in gold. Its upper level has two layers of tiled roof with upturned corners, and a railing runs around its terrace.
Trees and palm leaves frame the building, and a low wall stands in front.
The photograph (9 March 2013, by Emmanuel Brunner, described by him as the citadel of Hanoi at nightfall) shows a floodlit two-story building with a double tiled roof with upturned corners, a balustraded terrace, lattice windows and arched doorways, framed by trees and palm fronds. No source identifies which building it is.
UNESCO notes that older buildings, such as Doan Mon Gate and Hau Lau Palace, have been restored and modified over time.
Amazing facts
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Under the ground, there are remains from about 13 centuries!
Digging at 18 Hoang Dieu uncovered remains from about 13 centuries of history, layer upon layer.
The 18 Hoang Dieu excavations revealed a chronology spanning around thirteen centuries, from the 8th to the 19th.
-
The Flag Tower has a staircase that goes round and round inside!
The Flag Tower, built in 1805, has a spiral staircase in the middle that leads to the top.
Ky Dai, the Flag Tower (1805), rises 33.4 m in two stepped levels, with a central spiral staircase to the top.
-
The old palace was built on top of even older palaces!
Kinh Thien Palace, from the early 1400s, was built on the foundations of palaces from the 1000s and 1100s.
Kinh Thien Palace (early 15th century) was built on the foundations of earlier royal palaces of the 11th and 12th centuries.
Words to know
- citadel
- a strong, walled place where rulers lived, worked or defended a city
- dynasty
- a family of rulers who rule one after another
- foundations
- the lowest part of a building, on which the rest stands
- archaeologist
- a scientist who digs up and studies things people left long ago
- delta
- flat land where a river spreads out before it reaches the sea
- World Heritage Site
- a place UNESCO lists as important for all people
Discovery challenge
-
In which city is the Imperial Citadel of Thang Long?
The Imperial Citadel of Thang Long is in the heart of which capital city?
In which capital does UNESCO's Central Sector of the Imperial Citadel of Thang Long lie?
- Hanoi
- Bangkok
- Tokyo
Show the answer
Hanoi
Hanoi!
Hanoi, Vietnam.
Hanoi.
-
In which century was the citadel built?
In which century did the Ly dynasty build the citadel?
In which century does UNESCO date the building of the Thang Long Imperial Citadel?
- The 11th century
- The 18th century
- The 20th century
Show the answer
The 11th century
The 11th century!
The 11th century.
The 11th century.
-
How tall is the Flag Tower?
How high is the Flag Tower, built in 1805?
What height does ICOMOS give for Ky Dai, the Flag Tower?
- 33.4 meters
- 3.4 meters
- 334 meters
Show the answer
33.4 meters
33.4 meters!
33.4 meters.
33.4 m.
-
Which river's delta is the citadel built on?
The citadel was built on drained land from the delta of which river?
Land reclaimed from which river's delta lies under the citadel?
- The Red River
- The Nile
- The Amazon
Show the answer
The Red River
The Red River!
The Red River.
The Red River.
-
When did the citadel become a World Heritage Site?
In which year did UNESCO list the central sector of the citadel?
In which year was the Central Sector of the Imperial Citadel of Thang Long - Hanoi inscribed?
- 2010
- 1910
- 1810
Show the answer
2010
2010!
2010.
2010.
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Hanoi is the capital of Vietnam, in Southeast Asia. It grew beside the Red River, where a city called Thang Long was founded in 1010. Its old citadel is a UNESCO World Heritage Site, and its old quarter is known for its 36 streets. The 2019 census counted about 8 million people in the city and its surrounding districts.
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City
Hanoi
Hanoi is the capital of Vietnam, in Southeast Asia. It grew beside the Red River, where a city called Thang Long was founded in 1010. Its old citadel is a UNESCO World Heritage Site, and its old quarter is known for its 36 streets. The 2019 census counted about 8 million people in the city and its surrounding districts.
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For parents & teachers
What children will learn
- Explain what a citadel is and why rulers built them.
- Describe how archaeologists learn from layers in the ground.
- Explain how a place can be rebuilt many times over hundreds of years.
Recommended ages: 4 to 17 · About 15 minutes
Talk about it
- Why might rulers build a new citadel on top of an older fortress?
- What can old drains and pottery tell us about how people lived?
- Why might a country move its capital to a different city?
Try at home or in class
- Make layers of different colored sand or clay in a clear cup, bury small objects in each layer, then dig down and record what you find.
- Find Hanoi, Hue and the Red River on a map of Vietnam.
Key vocabulary: citadel, dynasty, foundations, archaeologist, delta, World Heritage Site
Where these facts come from
- Wikidata , Wikimedia Foundation (CC0 1.0)
- Central Sector of the Imperial Citadel of Thang Long - Hanoi , UNESCO World Heritage Centre
- Advisory Body Evaluation: Imperial Citadel of Thang Long - Hanoi, No 1328 , ICOMOS / UNESCO World Heritage Centre
- File:Citadelle de Hanoi 2.jpg , Wikimedia Commons
- UNESCO World Heritage List , UNESCO World Heritage Centre (Linked as a reference; site facts come from Wikidata)
- Wikimedia Commons , Wikimedia Foundation (Per file (public domain, CC0, CC BY or CC BY-SA); see each media record)
Checked, not yet human-reviewed. Last updated November 1, 2026. Spotted a mistake? Tell us.