Video: Sept. 18, 1862 (at 56:42)

(Thursday, September 18, 1862, part of the Maryland Campaign during the American Civil War) — On the day after the Battle of Antietam, the bloodiest battle day in U.S. history, Confederate General Robert E. Lee’s army prepared to defend against a Federal assault that never came.

After an improvised truce for both sides to recover and exchange their wounded, Lee’s forces began withdrawing across the Potomac in the evening to return to Virginia.