Editing World War I

One of the long-term causes of the war was the resurgence of imperialism in the foreign policies of the great powers of Europe. More immediately, the [[assassination of Archduke Franz Ferdinand]] of Austria, the heir to the throne of Austria-Hungary, on 28 June 1914 by Yugoslav nationalist [[Gavrillo Princip]] (a member of a secret society known as the [[Black Hand]]) in Sarajevo triggered a diplomatic crisis when Austria-Hungary subsequently delivered an ultimatum to the Kingdom of Serbia. Several alliances formed over the previous decades were invoked. Within weeks, the major powers were at war and, via their colonies, the conflict soon spread around the world.  On 28 July, the Austro-Hungarians fired the first shots of the war as preparation for the invasion of Serbia. While the Russians mobilized, the Germans under Kaiser [[Wilhelm II]] invaded neutral Belgium and Luxembourg on the way to France, providing a ''casus belli'' for Britain's declaration of war against Germany.

After the German march on Paris was brought to a halt—the so-called Miracle of the Marne—the Western Front settled into a static battle of attrition with a trench line that changed little until 1917. On the Eastern Front, the Russian army was successful against the Austro-Hungarians, but was stopped in its invasion of East Prussia by the Germans. In November the Ottoman Empire joined the war, opening up fronts in the Caucasus, Mesopotamia and the Sinai. Italy and Bulgaria went to war in 1915 and Romania in 1916. In Russia, Tsar [[Nicholas II]]'s government collapsed in March 1917 and a subsequent revolution instigated by [[Vladimir Lenin]] and his Bolshevik faction in November brought the Russians to terms with the Central Powers. After a 1918 German offensive along the western front, the Allies drove back the Germans in a series of successful offensives and American forces began entering the trenches. Germany, which had its own trouble with revolutionaries, agreed to an armistice on 11 November 1918.