What is the fine-grained topic of the following text: From the dark days of World War II, when the Allied nations foresaw international collaboration in the service of peace, to the actual Charter of the United Nations and its ratification in the spring and fall of 1945, to the first General Assembly of the then-51 member states in January 1946, you get a sense of early gropings toward the "one world" that those pioneers envisioned. Only return the topic.
Formation and early history of the United Nations