Uma vez perguntaram a Einstein quais seriam as armas que iriam ser utilizadas na Terceira Guerra Mundial. O cientista pensou e respondeu: As da Terceira não sei mas as da Quarta serão seguramente os paus e as pedras

Einstein was once asked what weapons would be used in the third world war. The scientist thought and answered: I know not with what weapons World War III will be fought, but World War IV will be surely fought with sticks and stones