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?

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.

Yes, you are correct in identifying several major events in the year 1945 that had significant impacts on U.S. history. Each of these events can be considered a turning point in its own right, but let's examine them to determine the one that could be considered the major turning point.

1. WWII ends: The end of World War II in 1945 is indeed a major turning point in U.S. history. It marked the conclusion of a devastating global conflict and solidified the United States as a superpower on the world stage. The war's end brought about significant changes in political, economic, and social aspects of the United States, including demobilization of the military, the return of soldiers to civilian life, and the beginning of the post-war economic boom.

2. Atomic Age begins: The United States' development and use of atomic bombs in 1945 marked the beginning of the Atomic Age. While this event had a profound impact on U.S. history and international relations, it may not necessarily be considered the major turning point as it was consequential specifically in the realm of atomic weaponry and the ensuing Cold War.

3. Creation of the United Nations: The establishment of the United Nations (UN) in 1945 aimed to prevent future global conflicts and promote international cooperation. While this event was significant in shaping the future of international diplomacy, it may not be considered the major turning point in U.S. history itself, although it did have a substantial impact on the U.S. foreign policy framework.

4. The Cold War: The tensions between the United States and the Soviet Union, known as the Cold War, emerged in the aftermath of WWII. While the Cold War began to take shape in 1945, it was a prolonged period of geopolitical rivalry rather than a distinct event, making it less likely to be considered the major turning point on its own.

Considering the above events, it can be argued that the major turning point among those you listed is the end of World War II. The war's conclusion significantly shaped the trajectory of the United States on a global scale and initiated a transformative era in American history. It led to numerous changes, including the United States becoming a world power, the beginning of the post-war economic boom, and the start of the Cold War. Additionally, the end of WWII also marked the beginning of the end for colonialism, as it challenged the imperial powers' hold on territories around the world.

Overall, while all the events you mentioned are indeed significant, the end of World War II holds particular weight in terms of its profound impact on U.S. history and its role as a major turning point.