World War I (1914 to 1918) was a global conflict primarily centred in Europe. It emerged from a complex web of political, economic, and territorial rivalries among major powers. The war saw the widespread use of trench warfare, chemical weapons, and technological innovations like tanks and aircraft. It resulted in immense casualties and profound social upheaval. The Treaty of Versailles in 1919 formally ended the conflict, imposing harsh terms on Germany and setting the stage for future conflicts.