Why was the cold war an important turning point in world history?

It was the first time in history where the world was on the brink of nuclear war. No longer did soldiers need to be involved in a conflict, now countries had the nuclear capabilities to destroy each other. what stopped them was the concept of mutually assured destruction which meant that if one country fired the other would and they would both be wiped out. 

He would most likely post his laws in the city market