History of the United Nations

Two images side by side of the UN Secretariat building. At left under construction in 1949. At right, in 1990 with the General Assembly building.

As World War II was about to end in 1945, nations were in ruins, and the world wanted peace. Representatives of 50 countries gathered at the United Nations Conference on International Organization in San Francisco, California from 25 April to 26 June 1945. For the next two months, they proceeded to draft and then sign the UN Charter, which created a new international organization, the United Nations, which, it was hoped, would prevent another world war like the one they had just lived through.

Four months after the San Francisco Conference ended, the United Nations officially began, on 24 October 1945, when it came into existence after its Charter had been ratified by China, France, the Soviet Union, the United Kingdom, the United States and by a majority of other signatories.

Now, more than 75 years later, the United Nations is still working to maintain international peace and security, give humanitarian assistance to those in need, protect human rights, and uphold international law.

At the same time, the United Nations is doing new work not envisioned for it in 1945 by its founders. has set  for 2030, in order to achieve a better and more sustainable future for us all. UN Member States have also agreed to to limit global warming.

With many achievements now in its past, the United Nations is looking to the future, to new achievements.

The history of the United Nations is still being written.

Milestones in UN History

Peru delegation signing the UN Charter in June 1945

Timelines by decade highlighting key UN milestones

The San Francisco Conference

A panoramic view of San Francisco, California in 1945 with San Francisco Bay in the background

The story of the 1945 San Francisco Conference

Preparatory Years: UN Charter History

The Palais des Nations in Geneva

The steps that led to the signing of the UN Charter in 1945

Predecessor: The League of Nations 

An aerial view of the Palais des Nations in Geneva

The UN's predecessor and other earlier international organizations