The assassination of Archduke Franz Ferdinand occurred on June 28, 1914. This event is widely recognized as the immediate catalyst for World War I. Archduke Franz Ferdinand, heir to the Austro-Hungarian throne, was killed in Sarajevo by Gavrilo Princip, a member of the nationalist group known as the Black Hand. The assassination heightened tensions between Austria-Hungary and Serbia, leading to a series of diplomatic conflicts and ultimately the declaration of war. This event is often viewed as the spark that ignited a larger conflict involving many of the world's powers, reshaping geopolitical alliances.