<p>It was to be the war to end all wars, and it began at 11:15 on the morning of June 28, 1914, in an outpost of the Austro-Hungarian Empire called Sarajevo. It would officially end nearly five years later. Unofficially, however, it has never ended: Many of the horrors we live with today are rooted in the First World War.</p> <p>The Great War left millions of civilians and soldiers maimed or dead. It also saw the creation of new technologies of destruction: tanks, planes, and submarines; machine guns and field artillery; poison gas and chemical warfare. It introduced U-boat packs and strategic bombing, unrestricted war on civilians and mistreatment of prisoners. But the war changed our world in far more fundamental ways than these.</p> <p>In its wake, empires toppled, monarchies fell, and whole populations lost their national identities. As political systems and geographic boundaries were realigned, the social order shifted seismically. Manners and cultural norms; literature and the arts; education and class distinctions; all underwent a vast sea change.</p>