Preliminaries This section requires expansion. The founding of the United Nations The idea for the future United Nations as an international organization emerged in declarations signed at the wartime Allied conferences: the Moscow Conference and the Tehran Conference in 1943.
From August to October 1944, representatives of France, the Republic of China, the United Kingdom, the United States, and the USSR met to elaborate plans at the Dumbarton Oaks Conference in Washington, D.C. Those and later talks produced proposals outlining the purposes of the United Nations Organization, its membership and organs, as well as arrangements to maintain international peace and security and international economic and social cooperation. Governments and private citizens worldwide discussed and debated these proposals.
At the Yalta Conference it was agreed that membership would be open to nations that had joined the Allies by 1 March 1945. Brazil, Syria and a number of other countries qualified for membership by declarations of war on either Germany or Japan in the first three months of 1945 – in some cases retroactively.
 Establishment On April 25, 1945, the United Nations Conference on International Organization began in San Francisco. In addition to governments, a number of non-government organizations, including Rotary International and Lions Clubs International received invitations to assist in the drafting of a charter. After working for two months, the fifty nations represented at the conference signed the Charter of the United NationsPoland, which was unable to send a representative to the conference due to political instability, signed the charter on October 15, 1945. The charter stated that before it would come into effect, it must be ratified by the Governments of the Republic of China, France, the USSR, the United Kingdom, and the United States, and by a majority of the other 46 signatories. This occurred on October 24, 1945, and the United Nations was officially formed.
The League of Nations formally dissolved itself on 18 April 1946 and transferred its mission to the United Nations.
 Activities The United Nations has achieved considerable prominence in the social arena, fostering human rights, economic development, decolonization, health and education, for example, and interesting itself in refugees and trade.
Main article: History of United Nations Peacekeeping The leaders of the UN had high hopes that it would act to prevent conflicts between nations and make future wars impossible. Those hopes have obviously not fully come to pass. From about 1947 until 1991 the division of the world into hostile camps during the Cold War made agreement on peacekeeping matters extremely difficult. Following the end of the Cold War, renewed calls arose for the UN to become the agency for achieving world peace and co-operation, as several dozen active military conflicts continued to rage across the globe. The breakup of the Soviet Union has also left the United States in a unique position of global dominance, creating a variety of new problems for the UN (See the United States and the United Nations). on June 26.