23,000 americans were casualites at the battle of Antietam during the civil war. 3600 were killed, 500 more than were killed on 9/11, 1100 more than were killed on D-day and 1200 more than were killed at Pearl Harbor. Antietam lasted only one day, and that is how many men were killed. Thats a very sobering thought. It’s also part of the reason I love to study the Civil War. So that the memories and the causes of the men who died during the Civil War will never be forgotten.