World War I began in 1914 when Russia and the Austro-Hungarian Empire started a conflict over the assassination of Austrian Archduke Franz Ferdinand. The assassination led to a chain of events that would ultimately lead to the First World War, which would last for more than four years and kill more than nine million people.

Arming for War: During the nineteenth century, European countries had spent large amounts of money and effort creating huge militaries. The new technologies provided by industrialization allowed them to build powerful weapons, such as dreadnoughts and submarines.

The Assassination of Archduke Franz Ferdinand:

The assassination of Archduke Franz Ferdinand in Sarajevo, Serbia on 28 June 1914 set off a chain of events that would eventually lead to the First World War. The assassination was traced to a Serbian extremist group that wanted to increase their power in the Balkans by breaking up the Austro-Hungarian Empire.

Imperialism:

Many of the warring countries had imperial goals in mind when they went to war. These included gaining strategic advantage in countries they had conquered and control over colonies they occupied in Asia or Africa.

In addition, the major European powers forged alliances with each other that guaranteed them support if they were ever to go to war. These agreements were not permanent, and they would change over the course of the war.

The war eventually became a global conflict between Britain, France, and Russia on one side, and Germany and Austria-Hungary on the other. More than twenty countries that controlled territory on six continents would declare war between 1914 and 1918, making World War I the first truly global conflict.