The twelve-hour battle of Antietam, 17 September 1862, was the bloodiest one-day battle in American history. Of nearly 100,000 soldiers engaged in the battle, about 23,000 were killed, wounded or missing. Six Brigadier and Major Generals were killed or mortally wounded. One soldier described the battle of Antietam as ‘an afternoon in the valley of death’. ANP/EPA/Michael Reynolds