Civil War no doubt, most other battles/wars someone had a superiority - except in the middle ages, but in the middle ages you weren't getting your bellybutton shot at while you were swinging your mace around.
In the Civil War, everyone lined up, fired at the enemy who was also lined up, then someone advanced. Many dropped on both sides, reload as fast as possible, then get another shot off. After that, bayonett time with people still being shot at. This was close quarters combat.
In an open field, one sided advanced with canon balls and a wall of shot coming at them.
Maybe there was something in europe equivelant to this? French Revolution?
WWI had trench warfare, while it was brutal, they still had trenches. Prior to that, all projectile armed warfare was out in the open.
-SW