2h 49min, sep 17, 1862 y - The Battle of Antietam
This battle occurred when Confederate general Robert E. Lee wanted to invade the North. He slipped his troops into Western Maryland. Luckily a Union officer found the battle plans of Robert E. Lee on the ground. Now McClellan decided to attack the Confederate Troops. This battle took place near a place called Sharpsburg, Maryland. Eventually Robert E. Lee retreated but this was the bloodiest day in the Civil War.
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Civil War Timeline