Many people look at the firing upon Fort Sumter as the spark that lit the Civil War but I think the real spark came back in 1859 when John Brown and his "army" of 21 attacked and occupied the armory at Harpers Ferry, VA.
The next day, US Marines under the command of US Army Colonel Robert E. Lee (how's that for irony) attacked Brown and his men. When the gun smoke cleared, 10 of Brown's men were dead (including 2 of his sons) and Brown was taken prisoner and shortly thereafter he was hanged. In fact on this very day 155 years ago.
I find it slightly amusing that most history books and mentions of Brown on the Internet either gloss over or omit completely the fact that Brown was almost certainly insane.
I'm not making any moral judgments on Brown's actions. I'm just saying that he was crazy. Seriously. When I first saw a picture of John Brown - I thought I was looking at Charlie Manson circa 1850.
The John Brown / Charles Manson analogy isn't that bad. Brown raided the armory because he wanted to arm slaves to start a full-fledged slave revolt. Charles Manson has said that he killed those folks in the Hollywood Hills because he hoped that blacks would be blamed and that would spark a race war in the US. This may be one of those things that I only find interesting.