150 years ago: On September 17, 1862, a turning point occurred in American history with the Battle of Antietam near Sharpsburg, Maryland, at Antietam Creek. It was the first major Civil War battle fought on Union soil and the bloodiest single-day battle in American history. Union Army Maj. Gen. George McClellan stopped the Confederate army of General Robert E. Lee on its march into the North. By sundown, savage and bloody combat resulted in nearly 23,000 combined casualties among the 100,000 soldiers engaged, including almost 4,000 dead. Lee’s retreat provided President Lincoln with the circumstance he needed to issue the Emancipation Proclamation, thereby redefining the Civil War – and the nation. Pictured: Union burial crew at Antietam by Alexander Gardner.