What year did World War I begin?

World War I began in 1914. The war erupted due to a complex web of alliances, imperial rivalries, and long-standing tensions among European nations. The assassination of Archduke Franz Ferdinand of Austria-Hungary by a Serbian nationalist group in June 1914 served as the immediate trigger for the conflict. This event led to a chain reaction, causing Austria-Hungary to declare war on Serbia, and subsequently, various countries to join the escalating conflict. The war lasted for over four years, resulting in significant casualties and widespread destruction across the globe.