The United Nations (UN) is an international organization of states established to maintain and strengthen international peace, security, and development of cooperation between countries.

The Charter of the Organization was signed on 26 June 1945 by representatives of 50 countries. Poland was not represented at the Conference and signed it later became the 51st founding state.

The United Nations officially exists since 24 October 1945. By this day the Charter was ratified by China, France, the Soviet Union, Great Britain, the United States and most other signatories. The 24th of October 24 is annually celebrated as the United Nations Day.

The preamble of the Charter points that the resolve of the peoples of the United Nations to "save succeeding generations from the scourge of war". The goals of the UN, as enshrined in its Charter, are maintenance of international peace and security, prevention and elimination of threats to peace, and suppression of acts of aggression, the settlement or resolution of international disputes by peaceful means, development of friendly relations among nations based on respect of the principle of equal rights and self-determination of peoples; international cooperation in economic, social, cultural and humanitarian fields,  promotion and development of respect for human rights and fundamental freedoms for all without distinction as to race, sex, language or religion. The UN Member States pledged to act in accordance with the following principles: sovereign equality of states; the settlement of international disputes by peaceful means; refusal in international relations from the threat of force or its use against the territorial inviolability or political independence of any state.

Currently 193 States are the members of the UN.

The Charter provides for the establishment of six main bodies of the UN: the General Assembly, the Security Council, the Economic and Social Council, the Trusteeship Council, the International Court of Justice and the Secretariat. The UN also has offices in Geneva, Vienna and Nairobi.

The UN General Assembly (UN General Assembly) is the main consultative body which consists of representatives of all the UN member states in which every country has 1 vote during voting procedure.

The UN Security Council which operates on a permanent basis. In accordance with the UN Charter, the UN Security Council is responsible for the maintenance of international peace and security. It is the responsibility of the UN Security Council to decide whether to send observers or UN peacekeeping forces, consisting of military units of the Organization member countries, to conflict areas in order to ease tensions and disengage the troops of hostile parties. During the entire period of the UN's existence, about 40 peacekeeping operations were conducted by UN peacekeeping forces. In 1988, UN Peacekeeping Forces received the Nobel Peace Prize.

The Economic and Social Council of the United Nations (ECOSOC) is authorized to conduct research and report on international issues in the field of economic, social, cultural, educational, health, human rights, environmental protection, etc., and to give recommedations on any of them.

The International Court of Justice, the main judicial body established in 1945, resolves legal disputes between states with their consent and gives advisory opinions on legal issues.

The UN Secretariat established to ensure proper conditions for the Organization's activities. The Secretariat is headed by the Chief Administrative Officer of the United Nations - the Secretary-General of the United Nations (since 1 January 2017 the UN SG is Antonio Guterres of Portugal).

The UN has a number of specialized agencies as international intergovernmental organizations on economic, social and humanitarian issues (UNESCO, WHO, FAO, IMF, ILO, UNIDO and others) associated with the UN, through ECOSOC, international agreements. The majority of UN members are members of the UN specialized agencies.

The UN system also includes autonomous organizations, such as the World Trade Organization (WTO) and the International Atomic Energy Agency (IAEA).

The official languages of the United Nations and its organizations are English, Arabic, Spanish, Chinese, Russian and French.

The UN headquarters is situated in New York.

In 2001, the UN and its Secretary-General Kofi Annan were awarded bye the Nobel Prize "For Contribution to the Creation of a More Organized World and the Promotion of Peace in the World".