We humans are unable to see polarized light, our eyes simply not being equipped to detect the planes of vibration associated with electromagnetic waves. This is no great handicap, as much of the light around us is unpolarised. However, some natural situations do generate polarized light, such as when sunlight, scattered from atmospheric molecules, makes the sky partially polarized; or light reflected from the sea. Some parts of the animal kingdom (mainly insects) have developed visual systems that are able to detect polarization in these and similar situations, and can apparently use this for navigation. Some have suggested that several millennia later, the Vikings, aided by naturally occurring Icelandic spar, were also able to us polarized light to navigate. More recently, we have discovered insects with extraordinarily sophisticated visual systems. Certain Stomatopod crustaceans for example, are not only able to detect the orientation, ellipticity and sense of rotation of polarized light, they are also able to detect the *degree* of polarization as well. As well, several species in the Scarabaeidae and Hybosoridae beetle families mainly reflect left circularly polarised light (cf. figure), and form one of Nature’s only natural sources of circularly polarized light. Quite why Nature has designed visual systems and exoskeletal structures in this way remains a mystery at present, but as well as describing some of these aspects of polarization in the natural world, I will hint at some recent developments.