Four years ago it was shown that the interpretation of string theory using the Kaluza-Klein idea of curled up dimensions comes with a remarkable twist. Two completely different possibilities for the curled up space (different sizes, shapes and number of holes) can, if properly chosen, give rise to identical observable physics. This is completely unexpected from a point particle viewpoint. The reason for this is that in point particle theories, the physical and mathematical descriptions of a geometric space are both based on considering it to be a collection of an infinite number of points grouped together in a particular manner. In string theory, the physical model is based on tiny loops and hence differs markedly from the mathematical description. This, in turn, allows two mathematically distinct curled up spaces to yield physically identical string models. This is a purely string theoretic phenomenon which relies profoundly on the extended nature of a string. Thanks for looking :)