Resumen
this article presents a conceptual, architectural and organizational model for the realization of a smart city based on a holistic paradigm as its cornerstone and on the new technologies as its enabling tools. The model is based on the concept of integration of the data belonging to different systems, through the development of a middleware, which allows the retrieval of data from various sources and their storage in a standard format in a new centralized database. The article also illustrates a real project concerning the integration of different sensor networks for the environmental monitoring that exemplifies and implements the main topics discussed. The issues related to its "governance" are also highlighted, not only from a strategic point of view, but also, and above all, from the perspective of its maintenance, which is an important and crucial feature for its "survival" over time.