The historical event known for the establishment of the United Nations occurred in 1945, following the conclusion of World War II. The UN was created to promote international cooperation, peace, and security to prevent future conflicts after the devastation of the war. Its founding was formalized with the signing of the UN Charter by 51 countries in San Francisco on June 26, 1945, and it officially came into existence on October 24, 1945. The establishment of the United Nations aimed to facilitate diplomatic dialogue and foster development, human rights, and international law, playing a crucial role in global governance.