The assassination of Archduke Franz Ferdinand in June 1914 triggered World War I. As the heir to the Austro-Hungarian throne, his murder in Sarajevo by a nationalist was the spark that ignited rising tensions among European powers. This event led to a complex web of alliances being activated, including Austria-Hungary's declaration of war on Serbia, which in turn brought Russia, Germany, Britain, and France into the conflict. The war marked a significant shift in global politics, with devastating consequences that reshaped national boundaries and societies, ultimately setting the stage for World War II.