At a conference in San Francisco in October 1945, 50 nations hammered out a new charter for world relations. It is essentially the constitutional document of the UN and is legally binding for all member states.
Those gathered declared: ‘We, the peoples of the United Nations, are determined to save succeeding generations from the scourge of war.’ The UN hoped to succeed where the League of Nations had failed during the 1930s and maintain peace and safety by means of collective security, which means that the security of one state is the concern of all. Every year, 24 October is celebrated as United Nations Day across the world.
Today, almost every fully recognised independent state is a member state of the UN, with membership currently totalling 193. The member states finance the UN’s work and govern its activities. To facilitate its role, as an international forum for discussion, the UN has adopted six official languages: Arabic, Chinese, English, French, Russian and Spanish.
Further reference: UN Charter.