In the Soviet Union, the Cold War developed out of a deep distrust of the United States and Great Britain that only became worse in the aftermath of World War II. In particular, it emerged from fears that the United States was extending its influence into Europe to an alarming degree, possibly even blocking Soviet plans to ensure a barrier of satellite states between the USSR and the West.
In the United States, on the other hand, the fear was that Stalin would expand Soviet influence westward into Western Europe, which would deny the Americans crucial allies and trading partners. US fears were exacerbated when communist armies seized control of China after a long and brutal struggle. The United States became committed to resisting the spread of communism, a policy that became known as containment.
Europe became the earliest "battleground" of sorts in the Cold War, as the United States and the USSR vied for influence in many of the nations most devastated by the conflict, where society and government was the least stable. The conflict between the two superpowers (a new term coined during the Cold War) left Europe divided, east from west, a situation which was most marked in Germany and elsewhere along the borders of the so-called "Iron Curtain."
The Truman Doctrine may have sparked the Cold War and heightened the tensions between the United States and the Soviet Union. In the United States, the Truman Doctrine stated that it would help countries threatened by the Soviet Union and the spread of communism. The United States demonstrated its intentions by aiding the anti-communist party during the Greek Civil War.
The Soviet Union stamped its authority on the Eastern Bloc and looked to expand its communist agenda to the rest of the world. The situation culminated in stiff competition with the United States, with each side trying to win over the different countries to their ideology.
Winston Churchill delivered the “Iron Curtain” speech calling for an alliance with the United States against the Soviet Union. Britain saw the U.S.S.R as a major threat, especially with regard to the control of Europe. The situation saw an alliance between France, Britain, and the United States (among other western allies), which formed the Western Bloc to oppose the Soviet Union’s Eastern Bloc.