United Nations milestones.

10 January 1946

First General Assembly, with 51 nations represented, opens in Central Hall, Westminster, London.

17 January 1946

Security Council meets for the first time in London, adopting its rules of procedure.

24 January 1946

General Assembly adopts its first resolution. Its main focus: peaceful uses of atomic energy and the elimination of atomic and other weapons of mass destruction.

1 February 1946

Trygve Lie of Norway becomes the first Secretary-General.

June 1948

First UN observer mission is established in Palestine--the UN Truce Supervision Organization (UNTSO).

10 December 1948

General Assembly adopts the Universal Declaration of Human Rights.

7 January 1949

UN envoy Ralph Bunche secures ceasefire between the new State of Israel and Arab States.

24 October 1949

Cornerstone is laid for the UN Headquarters in New York City.

27 June 1950

Security Council, acting in the absence of the Soviet Union, calls on Member States to help the southern part of Korea repel invasion from the north. The Korean Armistice Agreement is signed on 27 July 1953 by the UN Command and the Chinese-North Korean Command.

11 December 1950

Ralph Bunche becomes the first United Nations Nobel Peace Laureate.

1 November 1956

First Emergency Special Session of the General Assembly meets on the Suez Canal crisis, and on 5 November decides to establish the first UN peacekeeping force--the United Nations Emergency Force (UNEF).

September 1960

17 newly independent States, 16 from Africa, join the UN--the biggest increase in membership in any one year.

18 September 1961

Secretary-General Dag Hammarskjold dies in an aircraft crash while on mission to the Republic of the Congo (now the Democratic Republic of the Congo).

7 August 1963

Security Council votes voluntary arms embargo against South Africa.

4 March 1964

Security Council approves dispatch of peacekeeping force to Cyprus.

27 October 1966

General Assembly strips South Africa of its mandate to govern South-west Africa (now Namibia).

16 December 1966

Mandatory sanctions are imposed against Rhodesia (now Zimbabwe) by the Security Council.

22 November 1967

Following the six-day war in June 1967, the Security Council, after lengthy negotiations, adopts resolution 242 (1967) as the basis for achieving peace in the Middle East.

12 June 1968

General Assembly approves the Treaty on the Nonproliferation of Nuclear Weapons and calls for its ratification.

4 January 1969

International Convention on the Elimination of All Forms of Racial Discrimination comes into force.

25 October 1971

General...