Some events stand forever as markers in both the histories and the memories of nations. Such an event is the 1968 massacre of civilians in the village of My Lai, Vietnam, a slaughter carried out by United States soldiers. With such events it is sometimes assumed that we know everything we need to know, have seen what it is necessary to see, have heard all those who might speak. This documentary proves such assumptions wrong. Here we have more details, more film, more voices than have been previously collected in one presentation. We see and hear, for the first time on film, members of the unit that killed 507 unarmed men, women and children. We also hear and see survivors of that terrible day and the man who prosecuted the officer, Lt. William Calley, held responsible. This accumulated testimony, these personal accounts, serve to intensify the sense of bewilderment that accompanies any retelling of the My Lai story. It reveals anguish, suffering, rationalization, blame and the placing of blame. It well may be that there will never be an "explanation" for My Lai, but for assuring that even those who have no living memory of that event will not now be able to forget it, a Peabody Award is presented to "American Experience: My Lai."