And eventually what they had to do was build the Berlin Wall, which separated West Berlin from East Berlin. And really become symbolic of what the Cold War is all about. Other events, I mean we have the Korean War, a lot of this is the United States, so I want to be light on it. Because this is a world history course. But the Soviet Union invaded Czechoslovakia to keep it in its camp. They formed a gang, their bloods became the Warsaw Pact. And the United States and England joined NATO, the North Atlantic Treaty Organization.