World War I, also known as World War I, was a global war centered in Europe, beginning on July 28, 1914 and lasting until November 11, 1918. Since in which it occurred until the approach of World War II, it was called simply the World War or Great War, and later the First World War or World War I. In America, it was initially called the European War. More than 9 million fighters were killed; a casualty rate exacerbated by the belligerents' technological and industrial sophistication and tactical stalemate. It was one of the bloodiest conflicts in history, paving the way for major political changes, including revolutions in many of the nations involved. The war involved all the world's great economic powers, united in two opposing alliances: the Allies and the United States. Central Powers of Germany and Austria-Hungary. Although Italy had also been a member of the Triple Alliance along with Germany and Austria-Hungary, it did not join the Central Powers, as Austria-Hungary had taken the offensive against the terms of the alliance. These alliances were reorganized and expanded as more and more nations entered the war: Italy, Japan, and the United States joined the Allies, and the Ottoman Empire and Bulgaria the Central Powers. Ultimately, more than 70 million military personnel, including 60 million Europeans, were mobilized in one of the largest wars in history. Although a revival of imperialism was an underlying cause, the immediate trigger of the war was the assassination of Archduke Francis, on 28 June 1914. Ferdinand of Austria, heir to the throne of Austria-Hungary, by the Yugoslav nationalist Gavrilo Princip in Sarajevo. This triggered a diplomatic crisis when Austria-Hungary delivered an ultimatum to the Kingdom of Serbia... middle of paper... Militarism was widespread among the whites. Germany tried to build its own navy because Britain was the strongest at that time. Militarism may have primarily caused World War I because if a country believes it needs a well-built defense force, other countries will see it as a threat. Besides having a large army, taking control of a weaker country is another main reason that caused World War I. Imperialism is the belief that a country should enlarge its nation and take over other places. For example, Africa and Europe. Europe took control of Africa for its resources and power. Imperialism may also have primarily caused World War I because if a strong country takes over a weaker one, socially, economically or politically; how much conflict may occur because countries will compete for supremacy and resources. A country will try to have a strong and large army to try to imperialize a powerless republic.