On July 28, 1914, Austria-Hungary declares war on Serbia, effectively beginning the First World War. Within ~one week, the nations of Serbia, Austria-Hungary, Germany, Russia, France, Luxembourg, Belgium, and Great Britain were all at war. Over the course of the next four years, tens of millions of men from countries around the globe would fight and many would die in one of the bloodiest and most brutal conflicts in recorded history. World War marked a drastic change in the way wars were fought. The first examples of aerial and armored combat arose during the war. Trench warfare, massed artillery bombardments, long-range air raids, machine guns, and chemical warfare all characterized the conflict.

By the end of the conflict, ~11 million military personnel and ~7 million civilians had been killed through conflict and disease. The German, Austro-Hungarian, Ottoman, and Russian empires had been destroyed. Russia was embroiled in a civil war which would see the creation of another authoritarian state, the USSR, and the rise of communism. Political and economic strife, much of it a direct result of the war, would set the stage for the rise of fascism in such states as Germany, Austria, and Italy. Several nations would gain their independence at the end of the war, including Poland, Yugoslavia, Czechoslovakia, Latvia, Lithuania, Estonia, and Finland among others.