World War I, known as “The War to End All Wars,” had a very improbable beginning. While visiting Sarajevo, Bosnia, on June 28, 1914, Archduke of Austria Franz Ferdinand and his wife were both assassinated by Gavrilo Princip, a Serbian nationalist. Princip was a member of an organization seeking an end to Austro-Hungarian rule in Bosnia and Herzegovina. He was one of six conspirators who were involved in the plot. The assassination set off a chain of events that led to the outbreak of the First World War.
The assassination precipitated Austria-Hungary’s declaration of war against Serbia. The conflict escalated quickly with the Central Powers, consisting of Germany, Austria-Hungary and the Ottoman Empire, pitted against the Allied Powers, which included Great Britain, France, Russia, Italy and Japan. The United States joined the fray in 1917, and by the war’s end 32 countries were involved in the fighting.
Most of the battles were fought in Europe and the Middle East. Repeated attempts to outflank each other on the battlefield failed. This soon resulted in an uninterrupted line of entrenched positions on both sides. Barbed wire, coupled with machine guns, made crossing open ground to assault the enemy trenches suicidal to massed infantry advances. The conflict quickly settled into a stalemate, with both sides introducing new tactics and weapons in attempts to break the standoff. Soon new weapons appeared on the battlefield, including tanks, machine rifles and submachine guns. The most feared weapon was chlorine gas, which was first used by the Germans on the Western Front. Several types of gas soon became widely used by both sides.
In September 1918, the Central Powers began to collapse when Bulgaria capitulated, followed by the Ottoman Empire a month later. Finally, on November 11, 1918, an armistice was signed with Germany. The cease-fire was to take effect six hours later, at the 11th hour on the 11th day of the 11th month.
There was an estimated total, on both sides, of nine million combat-related deaths and another two to three million deaths caused by accidents and disease.