 Early attempts at military and political unity failed, eventually leading to the Treaties of Rome in 1957.The Second World War from 1939 to 1945 saw an unprecedented human and economic cost, in which Europe was affected particularly severely through the totality of modern warfare and large scale massacres such as the Holocaust.Once again, there was a widespread desire amongst European governments to ensure it could never happen again, particularly with the war giving the world nuclear weapons and two ideologically opposed superpowers.