World War 1 ended at 11am on 11 November 1918. Germany surrendered and the fighting ended with an armistice, an agreement to stop the conflict, while the terms of the peace were negotiated. On June 28 1919, Germany and the Allied Nations (including Britain, France, Italy and Russia) signed the Treaty of Versailles, formally ending the war.
Why did Germany lose?
At the start of 1918, Germany was in a strong position. Russia, one of Britain's allies (the Triple Entente), had left the war after the Russian Revolution and the seizure of power by Vladimir Lenin and the Bolsheviks in November 1917. Lenin wanted to concentrate on building up a communist state and wanted to pull Russia out of the war. He accomplished this by agreeing to the Treaty of Brest-Litvosk with Germany on March 3, 1918.
However, despite this, events moved against Germany. In April 1917 the powerful United States joined the war, American troops went into action just over a year later on the side of the Triple Entente. There was unrest at home for Germany, the population becoming tired of the war and the shortages it caused.
Germany and its allies knew that they had to launch a big offensive if they were to win the war before too many US troops arrived but this ‘Michael Offensive' failed and on 8 August 1918, the French and British armies launched the Hundred Days Offensive - a counter-attack, which pushed the Germans back.
By the autumn of 1918, Germany and its allies realised it was no longer possible to win the war and the allies began to withdraw, so that by the start of November, Germany was fighting alone. Kaiser Wilhem, the German leader abdicated on 9 November and on 11 November the armistice was signed.
The Treaty of Versailles
The leaders of the United States, Great Britain and France met in Versailles to decide on the terms of the peace, Germany, Austria and Hungary were not given the opportunity to negotiate and were presented with what the allies had decided. Though Germany protested they had little choice and it was signed on 28 June 1919.
This treaty was very harsh and it contributed to the reasons for the next World War twenty one years later. In it Germany had to accept total responsibility for the war, it lost large amounts of territory including Alsace-Lorraine, was banned from having an army larger than 100 000 men or having submarines or an air force. Germany also had to pay vast reparation of 132 billion gold marks, an impossible sum. The anger and privations this treaty caused helped form the groundwork for the rise of Adolph Hitler and the Nazi party and the Second World War.
References:
https://www.bl.uk/world-war-one/articles/how-the-first-world-war-ended
https://history.blog.gov.uk/2018/11/09/the-war-that-did-not-end-at-11am-on-11-november/