The American Expeditionary Force, under General John Pershing, entered the battle lines in significant numbers in April 1918. At the Battle of Belleau Wood, from June 1 to June 30, 1918, the Second Division, including the United States Marine Corps, helped clear out the German offensive threatening Paris.
On July 18, 1918, at the Battle of Chateau-Thierry, French and American forces went on the offensive.
The British Army, using a large number of tanks, attacked at Amiens on August 8 causing such surprise and confusion that German commander-in-chief, General Ludendorff, said it was “the blackest day of the German army.”
On September 12 the First United States Army, which had recently been organized from the American Expeditionary Force, eliminated the Saint-Mihiel salient, which the Germans had occupied since 1914. This salient threatened the Paris-Nancy railroad line. American forces were short of artillery support, which was provided by the French and British. This also was the first use of the U.S. Tank Corps, led by Lieutenant Colonel George S. Patton. Four days later, the salient was cleared out.
On September 26 American forces began the Meuse-Argonne Offensive, which continued until the end of the war. A key German observation post on Hill 305 in Montfaucon d’Argonne was captured on September 27. Approximately 18,000 Americans fell during this offensive. This was the first offensive conducted by the United States as an independent army. General Pershing’s general thrust was the Rhine River, which he expected to breach early in 1919.
On October 24 the Italian Army, with very limited American assistance, began the Vittorio Veneto offensive against the Austro-Hungarian Empire, which lasted until November 4.
End of the War
Bulgaria was the first of the Central Powers to sign an armistice (September 29, 1918, followed by Turkey (October 30) Germany requested a cease-fire on October 3, 1918, followed by Austria-Hungary. The fighting ended with an armistice agreed on November 11 at Compiègne. Austria and Hungary had signed separate armistices following the overthrow of the Habsburg monarchy.
When Wilhelm II. ordered the German High Seas Fleet to sortie against the Allied navies, they mutinied in Wilhelmshaven starting October 29, 1918. On November 9, a German Republic was proclaimed, marking the end of the 1871 German Empire. The Kaiser fled the next day to Holland, which granted him political asylum.
Distinguishing Features of the War
The First World War was different from prior military conflicts: it was a meeting of 20th-century technology with 19th-century mentality and tactics. This time, millions of soldiers fought on all sides and the casualties were enormous, mostly because of the more efficient weapons (like artillery and machine guns) that were used in large quantities against old tactics. Although the First World War led to the development of air forces, tanks, and new tactics (like the Rolling barrage and Crossfire), much of the action took place in the trenches, where thousands died for each square meter of land gained.
The First World War also saw the use of chemical warfare, and aerial bombardment, both of which had been outlawed under the 1909 Hague Convention. The effects of gas warfare were to prove long-lasting, both on the bodies of its victims (many of whom, having survived the war, continued to suffer in later life) and on the minds of a later generation of war leaders (Second World War) who, having seen the effects of gas warfare in the Great War, were reluctant to use it for fear that the enemy would retaliate and might have better weaponry.