5 September – On this day

Thirty miles north-east of Paris, the French 6th Army under General Michel-Joseph Maunoury begins attacking the right flank of German forces advancing on the French capital.

By the next day, the counter attack was happening along mush of the line. More than two million soldiers fought in the Battle of the Marne, and 100,000 of them were killed or wounded. On September 9, the exhausted Germans began a fighting retreat to the Aisne River. The Battle of the Marne was the first significant Allied victory of World War I, saving Paris and thwarting Germany’s plan for a quick victory over France.