What happened in 1914 that led the world war 1?

In 1914, the assassination of Archduke Franz Ferdinand of Austria-Hungary in Sarajevo by Serbian nationalist Gavrilo Princip set off a chain reaction of political tensions and alliances in Europe. Austria-Hungary declared war on Serbia, prompting Russia to mobilize in defense of Serbia. This escalation drew in other major powers due to existing alliances, leading to the outbreak of World War I as countries like Germany, France, and Britain became involved in the conflict. The complex web of alliances and nationalistic fervor ultimately transformed a regional dispute into a full-scale global war.