Facing massed German machine guns, the Marines made sweep after bloody sweep through Belleau Wood. Repeatedly accosted by the retreating French and urged to turn back, Captain Lloyd Williams of the 2nd Battalion, 5th Marine Regiment, uttered the now-famous retort, "Retreat, hell. We just got here." And indeed, by the end of that terrible June of 1918, the Marines had broken the back of the Germans powerful spring offensive. Their ferocity had earned...