How and why did the cold war take place?

Hence the name, 'cold war', the cold war is the war that never turned hot. It was the arms race between the Americans and the Russians, or as some like to think of it, capitalism and communism.

It all started after the end of the second world war, when the Russians, the British, The French and The US, all contributed to the defeat of the Nazi menace. The 4 countries decided to literally split Germany, and Berlin itself, into 4 pieces, to be ruled by the 4 different countries and their various laws.
However, soon, it became clear that there were hostilities building up between the Russian communist ideas and the others, especially the capitalist US. These hostilities grew and the Berlin wall was built, stopping contact between the communist part and the capitalist part. The relationship between Russia and the Allies deteriorated further, and nuclear war was thought to be imminent. In fact, the world was in particular concern for a few days after 'The Cuban Missile crisis' in the 60's.

This involved Cuba, one of the closest communists states to the US, to point nuclear missiles in the direction of America, literally ready at the press of a button, to launch. Every man, woman and child thought that the world was on the brink of nuclear war, however, when neither country made the preemptive strike, a bad peace continued. The most fascinating thing about the cold war was that no actual fighting ever took place. As the cold war continued, flaws started to become apparent in the communist system. Without the aid of any of the capitalist states, there simply was not enough resources to go around all the people. Also problems such as many of the people doubting their governments liability started to arise, and many Russians have been caught trying to escape over the border into a capitalist country, especially in Germany. Eventually, it seemed that nuclear war was an unlikely possibility for the first time in years.

The symbolic end to the cold war in 1995 was when the Berlin wall was finally taken down and the Russians finally gave up and accepted that communism was a good ideal, but it just doesn't work under the circumstances. 50 years of a massive build up, and the human race being cataclysmically close to doomsday, all because of a political disagreement. This was the closest the world has ever come to a nuclear war, but if it had, most have predicted that it would be the end of the world as we know it, and there would be very few, if any, human survivors.

There is lots on the cold war. I have simply summarised, as best as I can, the main reasons, causes and events. If you wish to know more there is absolutely tonnes about capitalism, communism, the Cuban missile crisis, the Berlin wall and everything else I have mentioned on Wikipedia, and all over the internet. I hope this helps you, and I hope I have not written too much!