What Countries Were Involved in World War I?

World War I, often called the Great War, was a war unlike any other that had ever been fought. Coming seemingly out of nowhere at a time of relative peace and prosperity, World War I's impact carried a legacy that heavily affected Europe during the first half of the 20th century and led to many of the issues that were central to the beginning of World War II. Consequently, the effects of World War I had tremendous far-reaching consequences that continue to impact the political and economic landscape.

The outbreak of World War I is typically attributed to the assassination and murder of Austrian Archduke Franz Ferdinand and his wife, Sophie, in June of 1914, but trouble was present in Europe before the attempt on Ferdinand's life. Conflicts in the Balkans between Russia, Austria-Hungary and Bosnia-Herzegovina were escalating, and Great Britain's naval supremacy was being threatened by Germany's increasing military prowess. By 1914, tensions amongst major European powers were running high, and the assassination of the Archduke by a member of the Young Bosnia coalition was the spark that ignited a global conflagration.

Immediately following the assassination, the conflict was a show of force from Austria-Hungary against Serbian terrorists like the one who had killed the Archduke and his wife. However, Austria-Hungary required the support of Germany and received it. Serbia, meanwhile, asked for aid from Russia. Germany subsequently declared war following Russian cooperation with Serbia. Eventually, the conflict would grow to a global scale, and the Central Powers of Austria-Hungary, Germany, Bulgaria and the Ottoman Empire would fight against Great Britain, the United States, France, Russia, Italy, Japan and Romania (the Allied Powers).

World War I went on for almost five years and cost over 20 million in lost lives across the globe. The warfare was especially horrific and soldiers suffered tremendously. Peace was ultimately brokered in late 1918 when Germany, initially in a strong position, signed an armistice agreement pressured by the leaders of their army. Germany had been losing against France, and the United States had recently joined the war, making the Triple Entente of Great Britain, France and Russia even stronger. It was no longer practical to continue to wage the war, and Germany's navy had gone on strike and refused to continue to fight. At Versailles in June of 1919, the war was officially over and was negotiated by the Allied Powers.