What event started the Cold War?

Stalin refused to allow free elections in Eastern Europe forcing nations to be Communist

Two atomic bombs were dropped on Japan.

Stalin was not invited to the Yalta Conference causing feelings of hatred towards the U. S

Soviet troops invaded the Rhineland, which concerned both Britain and the U. S

Growing out of post-World War II tensions between the two nations, the Cold War rivalry between the United States and the Soviet Union that lasted for much of the second half of the 20th century resulted in mutual suspicions, heightened tensions and a series of international incidents that brought the world’s superpowers to the brink of disaster.