After the end of the Second World War, the basic question of the future development of the world was how to preserve world peace and security, improve international cooperation and friendly relations among nations. These goals are enshrined in the founding Charter of the United Nations, which was signed on June 26, 1945 in San Francisco, and entered into force on October 24, 1945, after being accepted by 51 states. The UN replaced the ineffective League of Nations, founded in 1919.