Key Point: The war to end all wars...
On June 28, 1914, Archduke Franz Ferdinand of Austria-Hungary and his wife, Sophie, Duchess of Hohenberg, visited the city of Sarajevo and were assassinated by Gavrilo Princip, a 20-year-old Yugoslav nationalist. The assassinations triggered World War 1, which broke out a month later when Austria-Hungary declared war on Serbia. A series of alliances resulted in a rapid expansion of hostilities as Russia honored its treaty obligation with Serbia and declared war. Germany entered the war on the side of Austria-Hungary, and France and Great Britain soon joined the conflict as allies of Russia and Serbia.
The Triple Entente vs. the Central Powers
As the principal Allied Powers, also known as the Triple Entente, including Great Britain, France, and Russia, opposed the Central Powers, primarily Germany, Austria-Hungary, and later the Ottoman Empire, the conflict developed in to a series of devastating battles on land, sea, and air and escalated to a global scale. In the East, Germany’s great victory at Tannenberg in 1914 helped to spark revolution in Russia and took that nation out of the war in 1917 with the the separate peace of the Treaty of Brest-Litovsk. On the Western Front, great battles were fought along the Marne River, and at such locations as Ypres, Amiens, the Somme, and in Flanders. The war on the Western Front settled down to a contest of attrition, and the agony of trench warfare proved costly to both sides.
American Intervention Was a Deciding Factor in the Allied Victory