General U.S. Grant described the Battle of the Crater as "the saddest affair I have witnessed in the war." It occurred during the Union Army's siege of Petersburg, Virginia at the end of July, 1964.
During weeks of trench warfare much like what would occur in World War I, Union forces tunneled under the Southern lines and set off underground explosives that created a craterous gap in the Confederate defenses.
Unit after unit of Union troops were sent charging into and around the crater, but none got through. It was one of the Civil War's bloodiest struggles, claiming a combined 5,000 casualties, including much of the United States Colored Troops (USCT) under Union Brigadier General Edward Ferrero who were meeting Confederate soldiers face-to-face for the first time.