"The twentieth century has been a century of war. It began with the Boer War in South Africa and ended with the Gulf War in Kuwait and Iraq. This tragic legacy suggests that citizens of the twenty-first century have a shared responsibility to attempt to understand how and why these conflicts occurred and to discover how peace efforts contributed to the resolution of international conflicts. "
Primary sources devoted to helping people understand why the C20th was a time of such visceral conflict. If you believe Niall Ferguson it had to do with ethnic diversity in regions of deteriorating economic conditions and declining imperial control. My high school history teacher reckoned it was ideologies. Many of you will no doubt have other ideas...