Laos’s Plaine des Jarres (Plain of Jars) is a plateau within the Annamese Cordillera. The plain received its name because of the thousands of stone jars lying atop its flat surface. The jars vary in size; some are tall and skinny, others are short and fat. Each one possesses a hollowed-out center. The largest can hold an adult man.
No one is entirely sure of the origin of the jars or their purpose. One theory contends that the people of an ancient Lao kingdom quarried the stones from the nearby hills. Elephants then dragged the blocks of stone down to the plain. Once there, masons chiseled the rock into the shape of jars. Sculpted jars may have served as burial crypts or funeral urns for the elite of that ancient society.
During the Vietnam War, the soldiers of the Communist Pathet Lao and North Vietnamese Army established base camps in and around the Plain of Jars. They often set-up their camps close to the jars, knowing that U.S. rules of engagement forbid American pilots from dropping their bombs on Laos’s historic treasures.
At Phon Savan, Laos, the Pathet Lao erected a headquarters complex inside a cave located only a hundred yards from a cluster of jars. The jars kept the Pathet Lao safe. American air commanders refused to send B-52 bombers against the headquarters, fearing that U.S. bombs would destroy not only the headquarters but also the jars lying nearby. Nevertheless, the Americans still tried to knock out the cave headquarters with bombing runs by smaller, more accurate fighter-bombers. In the short space between the mouth of the cave and the jars, U.S. planes placed several bombs, none of which penetrated the cave itself.
In the 1960’s and 1970’s, the Plain of Jars became the scene of vicious fighting between the soldiers of Vang Pao’s CIA-backed Hmong militia and the Pathet Lao and North Vietnamese. The plain’s strategic importance rested on its proximity to the Mekong River to the south and the Ho Chi Minh Trail to the east.
The Communists sought control of the plain in order to forestall an American-sponsored attack from the west against their vital lifeline into South Vietnam. As early as November 1964, the U.S. National Security Council noted the relationship of the Ho Chi Minh Trail to Hanoi’s military activities in Laos. “…their [the Hanoi leadership’s] major concern in Laos is to keep the corridor and the areas bordering North Vietnam and China in Communist hands.” The Communists had another reason to dominate the plain – they hoped to jump-off from there to the Mekong River Valley, Indochina’s greatest geographical prize.
The Americans, who were barred from sending ground troops into Laos by the 1962 Geneva Agreement, instead deployed aircraft to keep the Communists restricted to the Plain of Jars. For nearly a decade, the Americans flew bombing missions against the plain and the roads leading south from it. Those airstrikes prevented the Pathet Lao and North Vietnamese from advancing to the Mekong Valley and the lands beyond.
George Kennan, a key architect of the American policy of containment, thought Communism should be contained primarily through economic means. Vibrant capitalist economies, and the materially-wealthy citizens of those economies, would halt the spread of Communism across the globe. Yet, by the middle 1960’s, Kennan’s containment policy had morphed into something altogether different. Across the Plain of Jars, the U.S. contained Communism with bombs.
 The Senator Gravel Edition, The Pentagon Papers: The Defense Department History of United States Decisionmaking on Vietnam, (Boston: Beacon Press, 1971), 653.