The start of the cold war started, when World War 2 ended. After WW2 the allies gave Germany to Russia and they also divided up Berlin into 4 sectors. Russia got the most eastern part of Berlin. Also in the treaty it said that Russia had control of all of the countries between eastern Berlin and Russia. Later Russia became stricter over them and made those countries become communist. America wasn't worried with Russia they were more busy with Japan. It stared heating up during the Korean and Vietnam. When the democratic side of both Korea and Vietnam were losing we became involved in those wars. Around When the Korean and Vietnam War started the reason that the United States got involved is because of the domino theory. That is if one country become communist then the countries around them will become communist. So then the Communist side of Korea and Vietnam were losing. Then Russia, being Communist, became involved in these wars. That started the hatred between the United States and Russia. The United States and Russia were butting head and had the fire power to blow up the world. Each of the countries had hydrogen bombs that would be able to blow up the entire world. No one wanted to fire the first shot. With Nuclear weapons near Russia, Russia decided to do the same thing to the United States. This turned into the Cuban missile crisis which would be the height of the Cold war. Both sides had deadly weapon. Anyone of them could have launched an attack. Luckily the whole incident was resolved in less than a month. The Cold War still carried on. During the late 70's and early 80's a Russian soldier was given word that the United States had launched a missile on Russia. The thing that told Russian this was a machine. What happened was that a certain cloud came into Russia and the machine thought it was a missile. The Soldier got ready to push the button and launch the missile. He rethought it and said no. He didn't push the button and he was fired and put into jail. They finally found out it was a cloud. Think about that. The cold war would later end with a famous quote. "Mr. Gorbachev, tear down this wall"