The Secret Bunker, a revolutionary relic of the General Staff Department within the Thang Long Imperial Citadel heritage site, has opened to the public for the first time.

Construction began on 10/2/1966 and was completed on 30/6 of the same year. The bunker, spanning over 37 square meters, played a crucial role in enabling the Vietnam People's Army High Command to maintain control, management, and command over various military branches and fronts during the bombing campaigns by the US Air Force against Hanoi. The bunker saw its most extensive use in 12/1972 during the height of the bombing of Hanoi and Hai Phong.

The entrance to the bunker features a staircase with iron handrails. The restoration of the bunker has adhered to the principle of respecting and preserving the original structure.

The sturdy iron door and frame are situated at both the entrance and exit of the bunker.

The ventilation system includes natural ventilation, filtration, and purification. It ensures adequate airflow when sealed, prevents the infiltration of toxic fumes from the outside, and contains air leakage from within, maintaining positive pressure inside the bunker.

The gravel wave dissipater exhaust system is part of the ventilation system, which comprises a gravel wave dissipater intake, a fine dust filter, a poison filter, a poison release lock, a fan, wind deflectors, a silencer, a flow meter, an automatic exhaust vent, and a gravel wave dissipater exhaust.

The bunker consists of two separate rooms connected by a door, with a ceiling height of approximately 2 meters.

Numerous artifacts related to the Vietnam War are currently on display in the rooms.

Officers and staff of the Cryptography Department, Cryptography Bureau, General Staff Department, pictured in front of the Cryptography Department office in 2/1972.

Many stamps and incoming telegrams marked "Secret" used during the Vietnam War are exhibited.

Personal belongings of the Cryptography Department officers from 1968 to 1992 are also showcased.

The use of technology in the presentations has proven attractive to visitors, especially younger generations.

The bunker has one entrance and one exit, 50 meters apart. The opening of the Secret Bunker to the public is part of a series of events commemorating the 80th anniversary of the August Revolution and National Day (2/9).

Thanh Hai