Trivia: What country’s declaration of war triggered the start of World War I?
Austria-Hungary
Ottoman Empire
United Kingdom
Germany
Correct Answer: Austria-Hungary
So why is this answer correct? : After Bosnian Serb Gavrilo Princip assassinated Archduke Franz Ferdinand, Austria-Hungary declared war on Serbia in July 1914. Its ally, Germany, then declared war on Russia. The rest is World War I history.