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The total timespan of the war
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On June 28, 1914, the heir to the Austro-Hungarian throne, Archduke Franz Ferdinand, was assassinated in Sarajevo by Gavrilo Princip, a Serbian nationalist. -
Austria-Hungary declares war on Serbia, starting the war.
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Germany declares war on Russia and France, and Britain declares war on Germany.
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The Battle of Tannenberg, a major German victory over Russia
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The First Battle of the Marne halts the German advance toward Paris
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The First Battle of Ypres, marking the beginning of trench warfare.
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Britain and France declare war on the Ottoman Empire
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Germany initiates a policy of unrestricted submarine warfare
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The Second Battle of Ypres was fought from 22 April – 25 May 1915, during the First World War, for control of the tactically valuable high ground to the east and the south of the Flemish town of Ypres, in western Belgium. The First Battle of Ypres had been fought the previous autumn. -
Second Battle of Ypres (April 1915): The German army used chlorine gas for the first time, killing thousands of Allied soldiers and affecting over 10,000. This event marked the introduction of chemical warfare on the Western Front. -
Allied forces land on the Gallipoli Peninsula in the Ottoman Empire.
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A German U-boat sinks the passenger liner Lusitania, killing 128 Americans.
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Germany begins the attack on Verdun, which becomes one of the longest and bloodiest battles of the war.
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The Battle of Jutland, the largest naval battle of the war, is fought between the British and German fleets.
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The United States declares war on Germany.
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The Third Battle of Ypres (also known as the Battle of Passchendaele)
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An armistice is signed, ending the fighting in World War I.