How did World War I end?
World War I ended on November 11, 1918, when Germany signed an armistice after its military position collapsed. The entry of the United States in 1917 tipped the balance, Germany's spring 1918 offensive failed, Allied counteroffensives broke through German lines, revolution erupted at home, and the Kaiser abdicated. The Treaty of Versailles formalized the peace in 1919.
The end of World War I came not through a single decisive battle but through the cumulative exhaustion of the Central Powers — a collapse that was military, economic, and political simultaneously.
By 1917, the war had reached a gruesome stalemate on the Western Front, with millions dead and the front lines barely moved. Two developments broke the deadlock. First, the United States entered the war in April 1917 after Germany resumed unrestricted submarine warfare and the Zimmermann Telegram revealed German attempts to ally with Mexico against America. American industrial might and the promise of millions of fresh troops tilted the strategic balance irreversibly against Germany. Second, the Russian Revolution of 1917 and the subsequent Treaty of Brest-Litovsk (March 1918) took Russia out of the war, freeing German forces for the Western Front.
Germany launched a massive spring offensive in March 1918 — the Kaiserschlacht (Kaiser's Battle) — hoping to win the war before American forces arrived in strength. The offensive initially achieved dramatic breakthroughs, advancing further than any Western Front attack since 1914. But it outran its supply lines, suffered enormous casualties, and failed to achieve a decisive victory. German soldiers, advancing through Allied positions, discovered stockpiles of food and supplies that revealed how much better supplied their enemies were — devastating morale.
The Allied Hundred Days Offensive, beginning in August 1918, broke the German army. Using combined arms tactics — infantry, artillery, tanks, and aircraft coordinated together — Allied forces smashed through German defenses repeatedly. The German army, exhausted, demoralized, and outnumbered by the arrival of American troops, could no longer hold. Germany's allies collapsed first — Bulgaria in September, the Ottoman Empire in October, Austria-Hungary in November.
Internally, Germany disintegrated. Naval mutiny at Kiel in late October spread into a general revolution. Workers' and soldiers' councils formed across the country. Kaiser Wilhelm II abdicated on November 9 and fled to the Netherlands. The new civilian government had no choice but to sign the armistice, which took effect at 11:00 AM on November 11, 1918 — the eleventh hour of the eleventh day of the eleventh month. The formal peace came with the Treaty of Versailles in June 1919, but its punitive terms planted the seeds of the next catastrophe.