The rest of the paper is organized as follows. Section II overviews the services that are commonly associated to the Smart City vision and that can be enabled by the deployment of an urban IoT. Section III provides a general overview of the system architecture for an urban IoT. More in detail, this section describes the web service approach for the realization of IoT services, with the related data formats and communication protocols, and the link layer technologies. Finally, Section IV presents the “Padova Smart City” project, which exemplifies a possible implementation of an urban IoT and provides examples of the type of data that can be collected with such a structure.