On July 15, 1918, near the Marne River in the Champagne region of France, the Germans begin what would be their final offensive push of World War I. Dubbed the Second Battle of the Marne, the conflict ended several days later in a major victory for the Allies.

The German general Erich Ludendorff, convinced that an attack in Flanders, the region stretching from northern France into Belgium, was the best route to a German victory in the war, decided to launch a sizeable diversionary attack further south in order to lure Allied troops away from the main event. The resulting attack at the Marne, launched on the back of the German capture of the strategically important Chemin des Dames ridge near the Aisne River on May 27, 1918, was the latest stage of a major German offensive—dubbed the Kaiserschlacht, or the “kaiser’s battle”—masterminded by Ludendorff during the spring of 1918.

On the morning of July 15, then, 23 divisions of the German 1st and 3rd Armies attacked the French 4th Army east of Reims, while 17 divisions of the 7th Army, assisted by the 9th Army, attacked the French 6th Army to the west of the city. The dual attack was Ludendorff’s attempt to divide and conquer the French forces, which were joined by 85,000 U.S. troops as well as a portion of the British Expeditionary Force (BEF), most of which were located in Flanders.

When the Germans began their advance after an initial artillery bombardment, however, they found that the French had set up a line of false trenches, manned by only a few defenders. The real front line of trenches lay further on, and had scarcely been touched by the bombardment. This deceptive strategy had been put in place by the French commander-in-chief, Philippe Pétain.

As a German officer, Rudolf Binding, wrote in his diary of the July 15 attack, the French “put up no resistance in front…they had neither infantry nor artillery in this forward battle-zone…Our guns bombarded empty trenches; our gas-shells gassed empty artillery positions….The barrage, which was to have preceded and protected [the attacking German troops] went right on somewhere over the enemy’s rear positions, while in front the first real line of resistance was not yet carried.” As the Germans approached the “real” Allied front lines, they were met with a fierce barrage of French and American fire. Trapped and surrounded, the Germans suffered heavy casualties, setting the Allies up for the major counter-attack they would launch on July 18.

READ MORE: Life in the Trenches of World War I