This episode tells how, faced with German forces only 25 miles from Paris, the British and French forces managed to stand firm. On 11th September, the Battle of the Marne was an incontestable victory. But although later it proved to be the decisive victory of the war, the Allies were not able to use it to swiftly end the hostilities. Instead, a few days later at Aisne both sides encountered the phenomenon of trench warfare. By the time of its culmination at the murderous battle of Ypres, the trench line was continuous from the sea to Switzerland. Show less