Final answer:
Gavrillo Princip, a member of The Black Hand, assassinated Archduke Franz Ferdinand and his wife Sophie in 1914, sparking the beginning of World War I.
Step-by-step explanation:
Gavrillo Princip, a member of the Serbian nationalist organization, The Black Hand, was the individual who assassinated Archduke Franz Ferdinand and his wife Sophie. On June 28, 1914, Princip seized the opportunity to shoot the Archduke and his wife when their motorcade took a wrong turn and stopped outside a cafe in Sarajevo. This assassination ultimately led to the outbreak of World War I.