The League of Nations (French: Société des Nations) is the first worldwide intergovernmental organisation whose principal mission was to maintain world peace. Its seat is in Geneva, Switzerland.
It was founded on January 10th in 1920 by the Paris Peace Conference after the end of the First World War. Since the time of philosopher Immanuel Kant, people had dreamed of a similar organisation. Now that US president Woodrow Wilson stood behind it and South Africa's prime minister Jan Smuts designed the architecture of the organization, it seemed to become reality.
Ran by the Executive Council (of which Britain, France, Italy, and Japan were the permanent members), the League had some successes in making countries outlaw slavery, fighting diseases, and negotiating at minor conflicts. Also, it administrated the former colonies of Germany and Arab territories ceded by the Ottoman Empire. As critics pointed out though, the fact that important decisions had to be done unanimously, would hamper the League in practice.
Since 1933, the weakness of the League became more and more obvious: The Axis Powers of Nazi Germany, fascist Italy and Imperial Japan left it; the Soviet Union was excluded after invading Finland, which didn't help either; and the USA never had become a member of it in the first place. The League's sanctions against Italy (during the Abyssinia conquest) and Francisco Franco's Spain (during the Civil War) proved to be useless. When World War II broke out, it had to be regarded a failure. Since 1939, the Council of the League hasn't met anymore. In early June 1940, about 75% of its staff was fired.