On the morning of September 17, 1862, 12,000 Union men tried to cross an exposed bridge at Antietam Creek. Only 450 Georgia sharpshooters positioned on a bluff opposite the creek (to the right in the above photo) were able to push back repeated charges for three and a half hours. Over 22,000 Americans lost their lives that day at the bridge and elsewhere at Sharpsburg. Discernible in photographs taken days after the battle is a sprig of a sycamore tree next to Burnside Bridge. Today it is known as the Witness Sycamore in honor of that day’s events.