Fifty years ago, one could see the top of the bunker from a high hill. To reach there, however, Vietnamese troops had to fight heroically during 55 days and nights, amidst numerous hardships and difficulties. Around the bunker were situated dense systems of defense lines, including many layers of barbed wires and four tanks. The bunker is 20m long and 8m wide. It consists of 4 compartments, which serves as both working offices and resident places.
One now can still find the iron vaults and sandbags atop the bunker. There used to be a roofed trench connecting the bunker of De Castries with the blockhouse at Cay Da in Hill A1. French troops piled up wooden planks and sandbags to make trenches. They took the wooden planks from the houses of the Vietnamese ethnic minority groups.
Inside this bunker, De Castries received such high-ranking officers as French Prime Minister Joseph Laniel, US President Dwight Eisenhower, British Prime Minister Winston Churchill, as well as well-known journalists. At 5h30pm on May 7th, 1954, Ta Quoc Luat, head of Company 360, Regiment 209, Division 312 captured alive General De Castries who was sitting at his desk in the corner of the bunker.

The tunnel had four compartments as follows:
Compartment 1
This is the office of Lieutenant Colonel Charles Piroth, who was in charge of French artillery in Dien Bien Phu. Prior to his departure to Indochina, Piroth submitted a tactical plan to Henri Navarre, in which he affirmed that �no artillery gun of Viet Minh could fire three times without being destroyed� in Dien Bien Phu. However, after experiencing the fierce attacks of Vietnamese artillery, Piroth committed suicide with a grenade in a tunnel at the end of Muong Thanh Bridge on March 15th, 1954. De Castries worried that his troops would lose their morale if they knew this so he had Piroth buried in the one end of Muong Thanh Bridge. Then he cabled to inform Navarre that Piroth had disappeared together with his jeep.

Compartment 2
This is the office of Seguin who was in charge of the French air force in Dien Bien Phu. He was tasked with the protection of the Muong Thanh and Hong Cum airfields. He himself faced shameful defeat. Before attack of Vietnamese troops, the French troops carried out around 100-150 sorties each day, transporting some 100-300 tons of goods to Dien Bien Phu. After assaults of Vietnamese troops, especially when the runways of Muong Thanh Airfield were cut off, French troops had to parachute goods to Dien Bien Phu, many of which came to hands of Vietnamese troops.

Compartment 3
This is the office of De Castriess secretary. Upon being promoted to the Commander of the Dien Bien Phu entrenched camp, he required to have this secretary, who was both a nurse and a journalist. When the Vietnamese troops attacked Dien Bien Phu on March 13th, 1954, De Castries asked her to come back to Hanoi by airway.

Compartment 4
This is the information and radio transmission center of the French troops in Dien Bien Phu.
When the Dien Bien Phu campaign ended, Vietnamese troops captured only one female French nurse, De Galard. She was among one of the first to be released under Vietnam policy.