Dien Bien Phu
Fought between 1946 and 1954, the First Indochina War reached its climax with the Battle of Dien Bien Phu between March and May of 1954. The French Far East Expeditionary Corps sought to destroy the Communist-nationalist revolutionaries known as the Viet Minh and regain control over the area of modern-day Vietnam, Cambodia, and Laos. However, the defeat of the French would be the final nail in the coffin of their Asian empire and lay the groundwork for the quagmire that would become the Vietnam War.
The French hoped to cut off supply lines the Viet Minh used to reach the Kingdom of Laos; they wanted to lure the Viet Minh into a conflict and defeat them once and for all. Under the leadership of Vo Nguyen Giap, however, the Viet Minh not only surrounded the French, but decimated their forces using weaponry the French never even suspected. The Viet Minh were vastly more familiar with the territory than the French; they were able to navigate the terrain, dig trenches, and burrow through mountains in ways the French could not even consider. After a siege lasting two months, truly a war of attrition, the French withdrew from the area and, ultimately, the region.
The results of the French defeat at Dien Bien Phu emerged at the Geneva Accords in 1954. The country of Vietnam was to be divided at the 17th parallel, with the northern part of the country under the control of the Viet Minh and Ho Chi Minh, known as the Democratic Republic of Vietnam, and the southern part of the country, led by Emperor Bao Dai, known as the State of Vietnam. This division, and the conflict to reunify the country as one nation, would eventually manifest as the Vietnam War.