Would anyone know the major event for the turning point in 1945 in US History?

I came up with:
WWII ends,
Atomic Age begins,
creation of the United Nations,
the Cold War,

Significance: the beginning of the end for colonialism

I don't know which is the major turning point...would it be WWII ends?

3 answers

As a child in 1945, I'd have said then that the end of WWII was most significant. We'd lived with war for almost 4 years and were excited and relieved when it ended.

However, in retrospect, I know feel that the beginning of the Atomic Age was most significant. The fear of atomic weapons still weighs heavily upon us. This fear kept restraints on the world during the Cold War. We still feel the threat of nuclear weapons in Iran, North Korea, and other countries.

http://en.wikipedia.org/wiki/Atomic_Age
So, the turning point of 1945 is the Atomic Age begins

and the others would be related events?

Thank You
Yes. All of these events are related.