“Smart city” is a term that covers many different facets and aspects. With four spectacular special stamps, Swiss Post has now lent it some artistic flair. The idea is irresistible: four internationally acclaimed exponents of street art – three male artists and one female – were given free rein to produce their personal interpretation of what the term “smart city” means to them. Four sheetlets have been created which reflect the concept’s wide-ranging aspects. There is no universally applicable definition of precisely what “smart city” signifies. It is instead a general term referring to a wide range of activities, ideas, innovations and technologies, which all have one thing in common – the holistic, environmentally-friendly and socially-responsible development of urban areas.