The international organization formed in 1945 to promote peace and security is the United Nations (UN). Established in the aftermath of World War II, the UN aimed to foster international cooperation, prevent future conflicts, and facilitate dialogue among nations. Its founding charter was signed by 51 countries, and it has since grown to include 193 member states. The UN engages in various activities, including peacekeeping missions, humanitarian assistance, and promoting human rights. Over the years, it has played a critical role in addressing global challenges, such as poverty, health crises, and climate change.