Explanation: <u>The main principles and structure of the United Nations Charter were determined by leaders at the United Nations Conference on International Organization (UNCIO) in Sans Francisco on April 25, 1945. After the war ended; the official United Nations Charter was ratified by 51 members on October 24, 1945. </u>
The United Nations (the UN) was established in 1945, the same year the Second World War ended. This organization was created in the hopes of averting such another massive war.