Over a year after the massacre on March 16, 1968, the reports of US soldiers involved in the killing of hundreds (347-504, contested) of unarmed civilians in and around the village commonly referred to as My Lai in South Vietnam.  While after action reports included observations from other soldiers and even members of the units involved of the killing of helpless civilians, and photos of the bodies were available, there was an effort by the US military to cover up the incident before it was eventually exposed on this date: the story was quickly picked up and spread by the major news networks.

美萊大屠殺中的英雄，用槍口對準(zhǔn)友軍的休·湯普森

Occurring in the aftermath of the surprise Tet offensive where thousands of Viet Cong guerrilla fighters dressed as civilians attacked US installations in February, the sweep of the My Lai village area resulted in the rounding up of hundreds of civilians, including children and infants, who were clearly non combatants and their summary murder.  Survivors managed to flee into the jungle and several dozen were rescued by US military helicopter crews (led by Warrant Officer Hugh Thompson Jr.) who witnessed the hours long operation and intervened.  While they filed reports, those reports were suppressed until the story was exposed over a year later.  22 US servicemen were put on trial, but only one, Lt William Calley Jr, was convicted.