Dan Snow hears the recollections of US soldiers who were sent to fight in France in 1918, and looks at the reactions of British and German soldiers to their arrival. They had received formidable physical training, but were naturally regarded as naïve by the battle-hardened 'old sweats' who'd served on the front for several years. But at the Battle of Bellau Wood, the Americans fought as tenaciously as any veteran unit, and helped to turn the tide of the war.