Three days after a German offensive near the Marne River in the Champagne region of France meets with failure, Allied forces launch a major counterattack on July 18, 1918, ending the Second Battle of the Marne and decisively turning the tide of the war toward an Allied victory.
After forces commanded by the German general Erich von Ludendorff fall painfully short of their objectives near the city of Reims on July 15–largely due to the deceptive Allied strategy of planting a line of false, lightly-manned trenches in front that would leave their real front line undamaged by the preliminary German bombardment–the Allied supreme commander, Ferdinand Foch, authorized a major counteroffensive. The Allied attack, which began in the early morning hours of July 18, 1918, was carried out by 24 divisions of the French army, as well as troops from the United States, Britain and Italy, pressing forward in some 350 tanks against the German salient.
As Crown Prince Wilhelm, a commander of the German forces at the Marne, recalled of the events of July 18: "Without artillery preparation, simply following the sudden rolling barrage, supported by numerous deep-flying aircraft and with unprecedented masses of tanks, the enemy infantry–including a number of American divisions–unleashed the storm against the 9th and 7th Armies at 5:40 in the morning." The French 6th and 10th Armies led the infantry advance, pushing forward five miles on the first day of the offensive alone. Meanwhile, the French 5th and 9th Armies launched supplementary attacks to the west. By the time the Germans ordered a retreat on July 20, the Allied counteroffensive in the Second Battle of the Marne had driven the Germans back from Chateau-Thierry to Soissons on the Aisne River, effectively reversing all the gains made in the region during the entire German spring offensive of 1918.
Casualties at the Marne were staggering, with Germany losing 168,000 soldiers to death or injury, compared with 95,000 for the French, 13,000 for the British and 12,000 for the U.S. After the disaster at the Marne, Ludendorff was forced to call off a planned German offensive further north, in the Flanders region stretching between France and Belgium, which he had envisioned as Germany's best hope of victory. In the end, the Second Battle of the Marne marked the last large-scale German offensive of World War I.