Symmetry is all around us. Our eyes and minds are drawn to symmetrical objects, from the sphere to the swastika, from the pyramid to the pentagon. Of fundamental significance to the way we interpret the world around us, this unique phenomenon indicates a dynamic relationship between objects. In chemistry and physics, the concept of symmetry explains the structure of crystals or the theory of fundamental particles. In evolutionary biology, the natural world exploits symmetry in the fight for survival. The symmetry is central to ideas in art, architecture and music. The Alhambra can help us to unlock the secrets of symmetry.