The correct answer to this open question is the following.
The reasons and historical events that led to the creation of the United Nations were the following.
The historical events can be traced back to the end of World War II, after the Allied forces defeated Germany, Japan, and Italy. The world witnessed too much suffering and destruction like never before seen. Even more, with the launching of the atomic bombs over Hiroshima and Nagasaki, Japan.
There were some previous charters, treaties, and agreements that inspired the foundation of the United Nations. We are talking about the Declaration of St. James Palace of 1941, teh Atlantic Charter of 1941, the Yalta Conference of 1945, and in the same year, the San Francisco, California Conference in the United States. All these works served to establish the foundation of the United Nations on October 24, 1945.
The United Nations differed from the League of Nations in that teh League of Nations was the result of the agreement between the main European superpowers after World War I, without the participation of the United States. Meanwhile, the United Nations was the result of the idea of 50 nations during the conference of San Francisco, California. There was a plurality of ideas that enriched the agreements to create the United Nations. Another important aspect of the UN that did no have the League of Nations, was the capacity of the UN to come up with resolutions that could be enforced. And this was not the case of the League of Nations. Another important consideration is that the United Nations promotes peace around the world, supports the progress of societies in all nations, and invites for the respect of human rights.