By the end of the 1950s, the ideological stand-off of the Cold War between the Western World and the Soviet Union had resulted in thousands of nuclear weapons being aimed by each side at the other. Strategically, the equal balance of destructive power possessed by each side situation came to be known as Mutually Assured Destruction (MAD), considering that a nuclear attack by one superpower would result in nuclear counter-strike by the other. This would result in hundreds of millions of deaths in a world where, in words widely attributed to Nikita Khrushchev, "The living will envy the dead".