The main cause of the 1914 outbreak of World War I can be attributed to a complex web of alliances, militarism, imperialism, and nationalism, exacerbated by the assassination of Archduke Franz Ferdinand of Austria-Hungary. This event triggered a series of diplomatic failures and mobilizations among European powers, leading to the escalation of conflict. Major alliances formed between the Allies and the Central Powers drew numerous nations into the war, resulting in a global conflict that had profound implications for the 20th century.