21°1′57″N 105°50′23″E

The Flag Tower of Hanoi (Vietnamese: Cột cờ Hà Nội) is a tower in Hanoi, Vietnam, which is one of the symbols of the city and once a part of the Hanoi Citadel, a World Heritage Site. Its height is 33.4 m (41 m with the flag).

The tower is considered to have been built in 1805 or 1812^[1] during the Nguyen dynasty as an observation post to the Hanoi Citadel. Unlike many other structures in Hanoi, it was not destroyed during the French invasion (1896-1897), and was continuously used as a military post. It is now located in the Vietnam Military History Museum.

Cột cờ is composed of three tiers and a pyramid-shaped tower with a spiral staircase leading to the top inside it. The first tier is 42.5 m wide and 3.1 m high; the second - 25 m wide and 3.7 m high and the third - 12.8 m wide and 5.1 m high. The second tier has four doors. The words "Nghênh Húc" (English: "To welcome dawn's sunlight") are inscribed on the eastern door; the words "Hồi Quang" ("To reflect light") - on the western door and "Hướng Minh" ("Directed to the sunlight") - on the southern door. The tower is lighted by 36 flower-shaped and 6 fan-shaped windows. The National Flag of Vietnam is on top of the tower.

• Tower of Hanoi