The world breathed a sigh of relief as the Allies entered Berlin and Germany raised its white flag. It had been a long war that lasted more than 30 years and saw the deaths of over 15 million people. But what was it that caused this conflict to escalate to such a global scale? It’s difficult to pin down the causes of world war but some historians argue that a number of deeper trends led to the outbreak.
One major cause was imperialism. Many European countries wanted to expand their empires and gain strategic advantages. This grew out of an era when the military was growing in importance and when nations decided loyalty on ethnic or cultural grounds rather than shared interests or ideals.
For example, the assassination of Archduke Franz Ferdinand of Austria tipped Europe into a war. The assassin was a Bosnian Serb nationalist named Gavrilo Princip who believed that the Slavic people in his country should have their own nation. This triggered Austria-Hungary to declare war on Serbia which then drew Russia into the conflict. From there, Germany drew in France by marching through neutral Belgium and then Britain which pulled the United States into the fight as well.