Due to the fact that I did not learn about the Civil War in 8th grade, my mom forced me to watch a 10-hour documentary on it by Ken Burns. It was called, creatively, The Civil War. I actually ended up enjoying the documentary, contrary to expectations, and it made an impression on me as one of the most horrific things I have ever watched. It was not gory, it was not particularly violent since it the only videos in it were interviews; it had facts, though, that said that the American Civil War was one of the most horrific wars that we have ever been through -- it is a close second after World War II. The reason that this was so horrific was because the fighting was so bloody (the third picture on the slideshow is the cross-section of a clay block shot by a black powder rifle; that's why people lost entire limbs in the Civil War), because of the sheer ferocity of the fighting, and because styles of warfare were changing. (click below to read more)
Fighting was becoming a bit more modernized, with armies shooting at each other instead of headlong charging into a fray with blades, but some people didn't understand that, and still thought that the bayonet was the best weapon to use. Brigadier General Burnside of the Union Army lost many thousands of men - ordinary, everyday men who had their own families, friends, and homes - in fourteen successive foot charges against Confederate soldiers. The Union soldiers were using bayonets, and the Confederates were using rifles. It was no contest. All those thousands of men died in one day, and there were other, equally bloody battles as well.