First Battle of the Marne - Wikipedia

On September 6, 1914, during World War I, the First Battle of the Marne began; French and British forces prevented a German advance on Paris (till the 12th Sept). From the article:

"The battle of the Marne was a major turning point of World War I. By the end of August 1914, the whole Allied army on the Western Front had been forced into a general retreat back towards Paris. Meanwhile, the two main German armies continued through France. It seemed that Paris would be taken as both the French and the British fell back towards the Marne River. The war became a stalemate when the Allied Powers won the Battle of the Marne. It was the first major clash on the Western Front and one of the most important single events in the entire war. The German retreat left the Schlieffen Plan in ruins and Germany had no hope of a quick victory in France. Its army was left to fight a long war on two fronts.

Field Marshall Sir John French, commander of the British Expeditionary Force (BEF), began to plan for a full British retreat to port cities on the English Channel for an immediate evacuation. The military governor of Paris, Joseph Simon Gallieni, wanted to organise the French and British armies to counter the weight of the German army's advance. After consulting Lord Kitchener about the use of British forces, Gallieni secured the overall command of the BEF, thus stopping Sir John's planned withdrawal. Gallieni's plan was simple. All Allied units would counter-attack the Germans along the Marne River, thus halting the German advance. As this was going on, Allied reserves would be thrown in to restore the ranks and attack the German flanks. On 5 September, in the mid afternoon, battle commenced when the French Sixth Army stumbled into the forward guard of the German First Army.

By 9 September, it looked as though the German First and Second Armies would be totally encircled and destroyed. General von Moltke suffered a nervous breakdown upon hearing of the danger to his two armies. His subordinates took over and ordered a general retreat to the Aisne River in order to regroup. The retreating armies were pursued by the French and British, although the pace of the Allied advance was slow – a mere 19 km (12 miles) in one day. The German armies ceased their retreat after 65 km (40 miles) at a point north of the Aisne River, where they dug in, preparing trenches that were to last for several years. The German retreat between 9 September and 13 September marked the abandonment of the Schlieffen Plan. Moltke is said to have reported to the Kaiser: "Your Majesty, we have lost the war." In the aftermath of the battle, both sides dug in and four years of stalemate ensued."