Evolution of human intelligence?

Human brains havent changed much since our anatomically modern ancestors evolved on the african plains. However, human beings have put men on the moon, discovered that energy and matter are really the same thing, we have created mathematics, literature, we don't just think, we believe and wonder about the nature of our existence, all with a brain that evolved to outsmart cheetas and build a shelter. Isn't a chimpanzee intelligence enough for that. What force gave us such a staggering intellect?