Not all colours in nature originate from pigments. Colour can also emerge if the microstructure of a material is fashioned into an optical diffraction grating. In nanotechnology, this capability of ‘structural colour’ is now within our grasp, and it is easy to imagine how it can be intelligently integrated into jewellery and artwork, vehicles and buildings. Beyond ‘static’ structural colour is a ‘dynamic’ form that could enable a full colour display where one material provides an infinite range of colours, security devices for identification and authentification, and military vehicles with active camouflage. Opportunities for intelligent colour are truly boundless.