Abstract. This work develops upon the concepts of Sentient City -living in a city that can remember, correlate, and anticipate -and Citizen Sensor Networks. We aim at technologies to interconnect people, allowing them to actively observe, report, collect, analyse, and disseminate information about urban events. We are investigating new methods and technologies to enhance administrators' capabilities in urban planning and management. We are proposing a platform to instrument citizens and cities, interconnect parties, analyse related events, and provide recommendation and feedback reports. The solution encompasses four types of elements: (i) mobile applications for intentional and non-intentional reporting of events; (ii) enhanced analytic models to centralize information, analyse the data, identify trends and operation patterns, and provide insightful information to decision makers; (iii) advanced social simulations to anticipate "what if" scenarios for infrastructure planning; and (iv) interfaces for monitoring, feedback, and recommendation. This research builds upon the IBM Smarter Cities project, part of the IBM Smarter Planet program. The outcomes of this research yield significant social contributions. By using it, administrators can make reliable decisions that will impact social services, traffic, energy and utilities, public safety, retail, communications, and economic development.