Video: 'Why France Lost The Battle of Dien Bien Phu 1954 (4K Documentary)' (May 7, 1954, at 17:02)

(Friday, May 7, 1954, 5:30 p.m. local time; during the Battle of Dien Bien Phu, part of the First Indochina War) — The 55-day Battle of Dien Bien Phu, fought in Vietnam between the French Union’s colonial Far East Expeditionary Corps and Viet Minh communist revolutionaries, ended this afternoon when rebel Viet Minh forces overran the French stronghold of Dien Bien Phu, bringing about the end of French control in Indochina and creating the division of Vietnam.

The end came at 5:30 p.m. when the “Determined to fight, determined to win” flag of the Vietnamese army was raised on the top of the command tunnel of French general De Castries.

Video: 'Vietnam The 10,000 Day War 03of26 Dien Bien Phu 720p' (May 7, 1954, at 20:44)

By the midnight, all the French troops were captured.

The French had begun an operation to insert, and support, their soldiers at Dien Bien Phu, deep in the autonomous Tai Federation up in the hills northwest of Tonkin to cut off Viet Minh supply lines into the neighboring Kingdom of Laos (a French ally), and draw the Viet Minh into a major confrontation in order to cripple them.

Video: 'Vietnam: A Television History, Part 2 The First Vietnam War (Unedited VHS version)' (May 7, 1954, at 43:17)

The Viet Minh, however, under General Võ Nguyên Giáp, surrounded and besieged the French.

They brought in vast amounts of heavy artillery (including anti-aircraft guns) and managed to move these bulky weapons through difficult terrain by individual men and women up the rear slopes of the mountains.

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They dug tunnels through the mountains and arranged the guns to target the French positions.

In March, the Viet Minh began a massive artillery bombardment of the French defenses.

The garrison was overrun in May after a two-month siege, and most of the French forces surrendered.