The spark that caused World War I was the assassination of Archduke Franz Ferdinand.
The spark that caused World War I was the assassination of Archduke Franz Ferdinand. To find this answer, you can study historical documents, books, or articles that detail the events leading to the outbreak of the war. Archduke Franz Ferdinand, the heir to the Austro-Hungarian throne, was assassinated on June 28, 1914, in Sarajevo, Bosnia-Herzegovina. His assassination by a Serbian nationalist named Gavrilo Princip led to a series of diplomatic tensions and military mobilizations that eventually triggered the war. Therefore, the correct response is "the assassination of Archduke Franz Ferdinand."
