How did 1 persons death set the motion a world war?

The assassination of Archduke Franz Ferdinand of Austria-Hungary on June 28, 1914, triggered a chain reaction of alliances and tensions that escalated into World War I. His death at the hands of a Serbian nationalist ignited existing rivalries and conflicts among European powers, leading Austria-Hungary to declare war on Serbia. This action mobilized allied nations, drawing in countries like Russia, Germany, and France, ultimately resulting in a global conflict. The interconnected web of alliances and militarism at the time meant that one event could rapidly escalate into a full-scale war.