The Banach−Tarski paradox is the suprising fact that any three-dimensional solid object can be "cut" into finitely many pieces which can be rearranged to form any other solid object. For example, a pea can be cut up and rearranged to form the sun. In this talk, we will discuss the proof of the Banach−Tarski paradox and especially the role of the infamous "axiom of choice." No specific mathematical background is required.