Answer:
- Amassing the largest armies ever in one place.
The Battle of Antietam was a standout amongst the most imperative occasions of the American Civil War. Battled on September 17, 1862, Antietam was the bloodiest single-day fight in American history with more than 23,000 losses (men recorded as killed, injured, caught or missing) in around 12 hours. The fight finished the Confederate attack of Maryland in 1862 and brought about a Union triumph. It additionally prompted President Abraham Lincoln issuing the Preliminary Emancipation Proclamation on September 22, 1862.