The United Nations (UN) was founded in 1945 to replace the League of Nations and promote international cooperation. It aims to maintain peace and security, protect human rights, and foster social and economic development. The UN flag features a map of the world surrounded by olive branches. It has six main organs including the General Assembly, Security Council, and Economic and Social Council. While the UN has achieved successes in areas like decolonization and humanitarian aid, it also faces ongoing challenges around conflicts, nuclear proliferation, and disparities between nations.