After World War II the United States and the USSR (Union of Soviet Social Republic) emerged as the two main powers in the world known as superpowers. Although they had fought together to defeat the Nazis in Germany differences between the two superpowers soon led to the start of the Cold War. The Cold War started in August 1945. It was a political war between the East and the West. It did not involve fighting, although there was a military threat on several occasions. They also sponsored wars and political unrest in other countries, destabilizing governments which they dis approved. In 1962, the two groups came very close to nuclear war. The Soviet Union moved missiles into Cuba, directly threatening the United States. The missiles were eventually removed only when the Americans threatened retaliation.