From 1914 to 1918 the world was immersed in a conflict without parallel. Whereas all previous wars had involved no more than a handful of nations at a time, the war that came to be known simply as The Great War engulfed most of the world, largely due to an intricate web of alliances that cascaded across the globe. 

When it was over, some 16 million people had been killed, a level of carnage that the world had never seen.