This work describes SenseCityVity, an approach to engage and support youth in a city in Mexico as they investigate, document, and reflect upon urban problems through mobile crowdsourcing. SenseCityVity focused on the development of a mobile crowdsourcing platform; the deployment of the Urban Data Challenge, codesigned by the authors' research team and actors to collect geolocalized images, audio, and video; and the analysis, appropriation, and creative use of the collected data for community reflection and artistic creation. The approach integrates mobile technology and community practices involving a large population of young people for urban engagement. The collective action generated a new multimedia dataset that is rich in terms of content and is enabling a number of studies aimed at better understanding the urban landscape of cities in the Global South. This article is part of a special issue on smart cities.