On November 11, 1918, the guns of the Western Front finally fell silent with the signing of the November 11 Armistice. While limited fighting still occurred in the farther corners of the world before the news could arrive, combat in the First World War had finally come to an end after four long, grueling, bloody years. Later treaties and legislation, most importantly the Treaty of Versailles, would officially end the war. By the end of the war, approximately 15 million to 20 million perished. The Weimar Republic replaced Imperial Germany and eventually gave way to the brutality of the Third Reich/Nazi Germany following the economic crises of the interwar period and the rise of Hitler and the Nazi Party. Tsarist Russia collapsed into a bloody civil war which concluded with the establishment of the Soviet Union, one the deadliest and most totalitarian regimes of the century. The Ottoman Empire fell and out of its ashes rose the modern nation of Turkey while the Ottoman territory in the Levant fell to the Allies. Austria-Hungary was forced to split into multiple successor states including Austria, Yugoslavia, Hungary, and Czechoslovakia. Russia lost control of Finland, Poland, and the Baltics as a result of its early withdrawal from the war. A greater sense of national pride and desire for autonomy arose within New Zealand and Australia following the Gallipoli Campaign and Canada for its service on the Western Front. The United States showed its potential to become a world power, a position which would be achieved in the Second World War.

World War One also saw drastic changes in the way war was waged. Gone were the days of mass groups of soldiers marching slowly across an open battlefield. Now machine guns and artillery dominated. New machines such as tanks and aircraft took warfare into new directions and dimensions. Chemical weapons were fielded on a large scale for the first time and, proving themselves so heinous, were seldom ever used again. Early semi-automatic and man-portable fully automatic weapons saw their combat debut, foreshadowing the next war.