I recommend Dan Carlin's "Blueprint for Armageddon" series about World War I. It'll take you a few days to get through it. The entire series is like 15 hours of audio. But I got a much greater appreciation for the causes behind World War I, and the events, than I ever have before. I'd not say I'm a fan of war history, but I am moved by the sacrifice of our forefathers (and mothers). He does a very good job of helping people get their heads around some of the staggering numbers of casualties in that war, and just how bad it was, and the very high level trends and forces that were at work before, during, and that continued after. It's also very interesting to me that the pre WWI world is a lot like our own--pretty prosperous, to the point you'd say war should be less likely since everyone understands the cost. But the world still fell into one of the worst conflicts in its history. Hopefully we've learned that lesson?