The German Army was marching through northern France while the British and French retreated before them. For over a week they had been trying to stay ahead of the German steamroller. They would turn to fight at the Battle of the Marne, a battle that some would later call a miracle.
The History of the Great war is now available on Stitcher
German advance before the battle courtesy of westpoint.edu
Battle of the Marne courtesy of westpoint.edu