The Battle of Dien Bien Phu marked the end of French control over Vietnam. For 55 days in 1954, over 10,000 French soldiers fought against 50,000 Viet Minh soldiers in a valley surrounded by mountains and jungle. Despite superior numbers and artillery supplied by porters, the Viet Minh defeated the French forces, demonstrating that an unconventional local force could overcome a conventional colonial power. This victory led to French withdrawal from Vietnam and growing US involvement to stop the spread of communism in Southeast Asia.