The United Nations (UN) was formed in 1945, the same year the war ended.
The end of World War II was the cause for the United Nations.
The most advanced nation in world war 2 was probably the united states.
After World War 2
United States
united states
The United Kingdom.
The League of Nations was formed at the end of World War One, the United Nations was formed at the end of World War II.
The United Nations was created to promote peace after World War 2.
the united states of America
The United States emerged from World War II as the richest, most powerful nation on Earth.
The United States, United Kingdom, the Soviet Union, and the remaining Allied Powers won World War II.
See link below on the development of the United Nations in 1945 after the war.