The Cold War is a term used to describe the era between the end of WWII (1945) and the end of the Soviet Union (1991). During this period of history there was much tension between the West and the East.
After WWII, the area that was occupied by the USSR became its satellite states. The territory that was occupied by the Allied powers was given back to the original countries.The Marshall Plan was the plan created by the U.S. to help rebuild Europe after the war. The plan was offered to the Soviet Union, they did not accept. The ideological differences slowly pushed the two superpowers apart and eventually the Soviet Union and its satellite states and communist allies became hostile towards the West.
Though there were many political and economic contests, like the space race and the buildup of nuclear weapons, there were also many proxy wars and much espionage.
The era was known as the Cold War, because although there were proxy wars, and wars that involved the U.S., there were no direct military confrontations between the big superpowers of the world durring this time. One of the major symbols of the Cold War was the Berlin Wall. When the Wall fell in 1989 it signaled the beginning of the end of the Cold War. Within two years, the Soviet Union was no more