Assassination of the Archduke Franz Ferdinand

The Assassination of the Archduke Franz Ferdinand was a major event that led a chain of events that started the First World War.

OverSimplified Background
Many regions in Austria-Hungary were unhappy about the government's rule. One such region was Sarajevo, who hated living in the country. The Archduke of Austria-Hungary, Franz Ferdinand, apparently didn't realize the hate and decided to go visit Sarajevo, pre-announcing his arrival in the newspaper.

During his car ride, there were a few assassination attempts on his life, including a bomb that missed his car but blew up another officer's car instead. The narrator hinted that the Archduke could've went into hiding, thus avoiding World War I. However, the Archduke decided to visit wounded soldiers instead. The car then turns a wrong turn and ends up right in front of Gavrilo Princip, who then kills him.

The Austria-Hungarian government is obviously angered about the assassination, and they placed blame on Serbia. The Austria-Hungarians brought in Germany as their backup, and in turn Serbia brought in Russia. Eventually, allies from each side joined each other, starting World War 1.

Historical event
Tensions between Serbia and Austria-Hungary have existed since the 1900s when a new dynasty started in Serbia. The new dynasty had friendly relationships with Russia but increasingly worse relationships with Austria-Hungary, especially over Austria-Hungary's annexation of certain regions as well as Serbia's growing military. Prior to Franz's assassination, numerous other assassination attempts on Austria-Hungarian officials took place.