The League of Nations officially comes into existence on January 10, 1920, when the Treaty of Versailles took effect, establishing the first worldwide organization aimed at maintaining world peace and promoting international cooperation after World War I. With its headquarters in Geneva, Switzerland.
The League of Nations held its first Assembly meeting on November 15, 1920, in Geneva, Switzerland. It was attended by delegates from 42 member states, symbolizing a new era of international diplomacy after World War I, though the U.S. never joined. More
