United Nations Organization (UN acronym according to abbreviationfinder), is the largest existing international organization. It is defined as a global association of governments that facilitates cooperation in matters such as international law, international peace and security, economic and social development, humanitarian affairs and human rights. Founded 24 of October of 1945, at the end of the World War II, as part of the agreements of the Conference of San Francisco, as a replacement for the old League of Nations.
Structured into various administrative bodies: General Assembly, Security Council, Economic and Social Council, General Secretariat, Trusteeship Council and the International Court of Justice. The main public figure of the UN is the Secretary General, a position held by the Portuguese socialist politician António Guterres, who took office on January 1, 2017  .
Main article: Charter of the United Nations .
The first commitment to establish a new international organization was contained in the Atlantic Charter, signed by US President Franklin Delano Roosevelt and British Prime Minister Winston Churchill on August 14, 1941, at a conference on board a warship. off the coast of Newfoundland.
Both leaders pledged to establish a “permanent and comprehensive system of general security” and expressed their desire to “achieve the maximum cooperation of all nations in the economic sphere.” The principles of the Atlantic Charter were accepted by the United Nations more generally in its Declaration, signed on January 1, 1942 by the representatives of the 26 allied nations against the powers of the Rome – Berlin – Tokyo axis during World War II. World. It was in this document that the term United Nations, which had been suggested by Roosevelt, was used for the first time officially.
In 1943, at a conference held in Moscow, efforts were started to create a new organization. On October 30 of that year, representatives of the Union of Soviet Socialist Republics (USSR), the United Kingdom, China and the United States signed a declaration in which they recognized the need to establish “in the shortest possible time a general international organization.”. During the Tehran Conference, a month later, Roosevelt, Churchill and the top Soviet leader Stalin They reaffirmed “the supreme responsibility that falls on us and on all the United Nations to create a peace that will banish the scourge and terror of war.”
Following the Moscow declaration, representatives of the four powers met in Dumbarton Oaks (Washington, United States) in the fall of 1944to study a series of proposals for the creation of an international organization. They approved a draft charter that specified its purposes, structure and operating methods, but were unable to agree on the voting method of the proposed Security Council, which would be the body that would have the greatest responsibility for matters relating to the maintenance of peace and security.
Harry S. Truman at the founding conference in San Francisco in 1945.
The problem of voting was resolved at the Yalta Conference (February of 1945), last negotiating summit to be attended by Roosevelt, Churchill and Stalin in the last of his encounters during the war. In short, the Soviet leader accepted the British and American position, which limited the prerogatives of the great powers in procedural matters, but maintained the right to veto in essential matters. At the same time, the allied leaders proposed that a United Nations conference be held to prepare the charter of the new organization.
Delegates from 50 nations met in the American city of San Francisco on April 25, 1945 for the officially called United Nations Conference on International Organization. Over two months, they produced a 111-article letter based on the Dumbarton Oaks draft. The Charter was approved on June 25 and signed the next day. It entered into force on October 24, 1945, after being ratified by the majority of the signatories. The ties that emerged from the war alliance against common enemies accelerated the agreement to establish this new organization.
The UN came into existence after the ratification of the Charter by the ROC, France, the Soviet Union, the United Kingdom of Great Britain and Northern Ireland, and the United States and the vast majority of the other 46 members. The first session of the General Assembly was held on January 10, 1946 in Central Hall Westminster (London). The League of Nations was officially dissolved on April 18, 1946, and handed over its mission to the United Nations.
In 1948, the Universal Declaration of Human Rights was proclaimed, one of the most outstanding achievements of the UN.
The founders of the UN expressed hope that the new organization would serve to prevent further wars. These wishes have not come true in many cases. From 1947 to 1991, the division of the world into hostile zones during the so-called Cold War made this objective very difficult, due to the veto system in the Security Council. Since 1991, the UN peacekeeping missions have become more complex, encompassing non-military aspects that ensure the proper functioning of civil institutions, such as in elections.
Recently there have been numerous calls for reform of the UN   . Some want the UN to play a greater or more effective role in world affairs, others want its role to be reduced to humanitarian work. There have also been numerous calls for membership in the Security Council to be increased to reflect the current geopolitical situation (that is, more members from Africa, Latin America and Asia) and for the Secretary General to be elected in presidential elections and a People’s Assembly. of the UN (UNPA) by direct voting of the citizens.