Which event sparked the start of World War I in 1914?

• A. The assassination of Archduke Franz Ferdinand
• B. The Invasion of Poland
• C. The Bombing of Pearl Harbor
• D. The Sinking of the Lusitania

Answer: (A)

The key idea is how a single triggering event can ignite a chain reaction among allied nations. The assassination of Archduke Franz Ferdinand of Austria-Hungary in Sarajevo in 1914 created an immediate crisis for Austria-Hungary. With tensions already high and a web of alliances in place, Austria-Hungary sought to punish Serbia, and Germany pledged support. That set off mobilizations and declarations of war across Europe, pulling Russia, France, Britain, and others into conflict and turning a regional dispute into a full-scale war. The other events happened later or were not the spark that started the war in 1914—Poland’s invasion occurred in 1939, the bombing of Pearl Harbor in 1941, and the sinking of the Lusitania, while significant, did not initiate World War I.