IDEAL-CITIES aims to develop, demonstrate and evaluate an open modular platform for building adaptive Internet-of-Things and Participatory Sensing (IoTPS) based Smart City applications, supported by Big Data analytics and Cloud services. IDEAL-CITIES outcomes will increase urban life quality, safety and inclusivity by enabling citizens and authorities to produce and exchange contextualised distributed intelligence and information in real-time, in a trustworthy and sustainable manner. The IDEAL-CITIES platform will foster the development and uptake of novel IoTPS-based Smart City applications and enhance the associated market base, by demonstrating new feasible ways for providing IoTPS applications and services which can contribute to urban citizen’s well-being and the cities’ circular economy. The IDEAL-CITIES platform will be demonstrated in the context of two fully-fledged IoTPS Applications, with a focus on mobility for the impaired and on citizen safety, in close cooperation with involved communities (a non-profit organisation for the blind and partially-sighted and four municipalities, respectively), validating the utility of the proposed platform and approach.