What major event is associated with the assassination of Archduke Franz Ferdinand?

The assassination of Archduke Franz Ferdinand of Austria-Hungary on June 28, 1914, is widely recognized as the immediate catalyst that triggered the onset of World War I. This event set off a chain reaction of political alliances and hostilities among the great powers of Europe. Following the assassination, Austria-Hungary issued an ultimatum to Serbia, whose response failed to satisfy the demands. This led Austria-Hungary to declare war on Serbia, which activated a system of alliances that brought in other nations, escalating the conflict into a full-scale war. The interconnected political landscape of Europe meant that what began as a localized issue quickly drew in multiple countries, leading to a global conflict that lasted until 1918. Thus, the correct association with the assassination of Archduke Franz Ferdinand is indeed the start of World War I.