The “Tough ’Ombres” of the Ninetieth Infantry Division saw action for the first time on the bloody battlefields of France on Sep. 12, 1918.The Great War (no one imagined there could be a second) has all but faded from the national memory. Ask most Americans what they know about World War I, and they may mumble something about trench warfare, the Lusitania and the Treaty of Versaill...