Which event is often cited as the spark that ignited World War I?

The assassination of Archduke Franz Ferdinand is widely regarded as the pivotal event that set off a chain reaction leading to World War I. This event occurred on June 28, 1914, when the heir to the Austro-Hungarian throne was killed in Sarajevo by a Serbian nationalist. His assassination intensified existing tensions within Europe, particularly between Austria-Hungary and Serbia.

Following the assassination, Austria-Hungary issued an ultimatum to Serbia that was intentionally harsh, hoping to provoke a conflict. The situation escalated as alliances and treaties among European powers activated, ultimately leading to the widespread mobilization of armies and the onset of war in just a few weeks.

Other events listed, such as the sinking of the Titanic, the bombing of Pearl Harbor, and the signing of the Treaty of Versailles, are significant in their own contexts, but they are not related to the origins of World War I. The Titanic disaster occurred in 1912 and did not bear any direct influence on the political landscape leading to the war. The bombing of Pearl Harbor was a critical event in World War II, and the signing of the Treaty of Versailles marked the end of World War I, rather than its beginning. Thus, the assassination of Archduke Franz