What triggered the first world war?

On June 28, 1914, Gavrilo Princip assassinated Archduke Franz Ferdinand, the heir to the Austrian throne, in Sarajevo. Gavrilo Princip was a member of Young Bosnia, a group whose aims included the unification of the South Slavs and independence from Austria (see also: the Black Hand). The assassination in Sarajevo set into motion a series of fast-moving events that escalated into a full-scale war. However, the reasons behind the conflict are multiple and complex.

Now in English--all the countries were building up their armies and taking sides to protect each other from conflict. This dude was killed for political reasons, and sparked a war between the two countries. Their allies had already promised to help them if they got into war, so all these other countries started joining in against each other until it was a world war. It was going to happen whether that dude was killed or not. It is like when you just know there will be a fight in school because of the tension in the air. The fight is just waiting for somebody to push someone else, then all the friends will jump in to help them.

On June 28, 1914, Gavrilo Princip assassinated Archduke Franz Ferdinand, the heir to the Austrian throne, in Sarajevo. Gavrilo Princip was a member of Young Bosnia, a group whose aims included the unification of the South Slavs and independence from Austria (see also: the Black Hand). The assassination in Sarajevo set into motion a series of fast-moving events that escalated into a full-scale war. However, the reasons behind the conflict are multiple and complex. Historians and political scientists have grappled with this question for nearly a century without reaching a consensus.

the main spark occured when gavrillo princip assasinated the archduke ferdinand in sarejevo. but the system of ententes and aliances made a regional conflict into a global one.

The assasination of a small time duke. Would you believe it?