"Antietam is the bloodiest day of the bloodiest war in American history," says historian Dennis Frye.
As Frye explains, within a twelve hour period two armies totaling about 130,000 men collided. It was a battle that would change the course of America's history.
"They open up with deadly accurate weapons. And the place just explodes," says Frye.
After the battle, Sunken Road became Bloody Lane because of the amount of blood in the soil from those who fought there.
"But today I realize I'm an American. People need to come to sights like this. To walk the ground of Bloody Lane. It's only a quarter of a mile long. Yet some 5,500 men were wounded and died here," says visitor, Curt Isler.
As part of the anniversary Antietam has brought in special speakers, presentations, and reenactors demonstrating how soldiers lived back in the day.
It was a reenactment of an American story that still impacts the public a century and a half later.