Which event sparked the beginning of World War I?

The assassination of Archduke Franz Ferdinand is recognized as the event that sparked the beginning of World War I. This incident occurred on June 28, 1914, when the heir to the Austro-Hungarian throne was killed by Gavrilo Princip, a member of a nationalist group seeking to end Austro-Hungarian rule over Bosnia and Herzegovina. This assassination set off a chain reaction of events, as it heightened tensions between Austria-Hungary and Serbia, which ultimately led to a series of alliances being activated and the declaration of war.

The assassination catalyzed existing political and military alliances in Europe. Austria-Hungary's subsequent declaration of war against Serbia activated Russia's support for Serbia, which in turn brought in Germany, France, and eventually a multitude of other nations into the conflict, thus escalating into a full-blown global war.

Understanding the assassination's significance helps contextualize the complex web of alliances and political tensions in early 20th-century Europe, which were long-standing issues that contributed to the outbreak of war.