What happened
France fortified the remote valley of Dien Bien Phu to lure the Viet Minh into a set-piece battle. Instead, General Vo Nguyen Giap’s forces hauled dismantled artillery over the mountains by hand and bicycle — a documented feat — and ringed the basin.
From March 13, 1954, the strongpoints were crushed one by one and the airstrip lifeline was cut. The garrison surrendered on May 7, 1954; common accounts put the prisoners at over 11,000.
Background
The battle came after eight years of the First Indochina War. The Geneva conference on Indochina opened the very next day, May 8.
Consequences
France quit Indochina. The Geneva Accords of July 1954 divided Vietnam at the 17th parallel pending elections that never came — the seed of the next war. The battle became a worldwide symbol of decolonization.