After the devastation of World War II, the need for an effective platform for international cooperation became increasingly apparent. The United Nations Charter was signed on June 26, 1945, at the San Francisco Conference, attended by representatives from 50 countries. Its primary aim was to prevent future conflicts and foster cooperation for social and economic development. The Charter officially came into effect on October 24, 1945, once it was ratified by the five permanent members of the Security Council—China, France, Russia, the United Kingdom, and the United States—and a majority of other signatory nations. This date is now celebrated annually as United Nations Day.

The Charter, consisting of a preamble and 111 articles, delineates the functions and powers of the various organs of the UN, including the General Assembly, the Security Council, and the International Court of Justice. It articulates key principles, such as the promotion of human rights, the importance of maintaining international peace and security, and the need for cooperation in solving global issues. The establishment of the UN marked a significant shift in international relations, as countries committed to collective problem-solving rather than unilateral actions.

In the subsequent months, the newly formed UN began its work by addressing pressing issues, including post-war reconstruction and the establishment of peacekeeping missions. Its influence grew as it provided a forum for dialogue and negotiation, aiming to resolve conflicts before they escalated into wars. Over the years, the UN has expanded its role to include various efforts in humanitarian aid, development, and the promotion of international law, significantly shaping global governance.