Members of Charlie Company, 1st Battalion, 20th Infantry Regiment, entered the hamlet of My Lai expecting Viet Cong resistance and instead rounded up and killed hundreds of unarmed civilians, mostly women, children, and the elderly. The massacre was covered up for over a year until Seymour Hersh's reporting and photographs by Ronald Haeberle forced a public reckoning, deepening American disillusionment with the Vietnam War.
Soldiers of Charlie Company had lost friends to booby traps and snipers in the weeks before, and commanders told them to expect a Viet Cong stronghold at My Lai. Instead they found farmers, children, and old men. Over several hours, troops shot villagers in ditches, burned homes, and killed livestock. Lieutenant William Calley personally ordered and participated in executions; one helicopter pilot, Hugh Thompson, landed his aircraft between soldiers and fleeing villagers and threatened to open fire on his own countrymen to stop the killing.
Army investigators initially reported the event as a battle with 128 enemy dead. It took the persistence of a soldier named Ron Ridenhour, who wrote letters to Congress and the Pentagon after hearing accounts from friends who had been there, to trigger an investigation. Seymour Hersh's 1969 exposé, paired with Haeberle's harrowing photographs of bodies piled on a dirt road, shattered the last official narrative that American forces were only fighting combatants. Calley was convicted of murder in 1971 but served just over three years under house arrest, a outcome that many Americans, on both sides of the war debate, found impossible to reconcile with the scale of what happened.