The idea was to create a youth participation experience around the common spaces of cities, involving both young people with fewer opportunities outside of training, formal education and job placement paths and young people actively involved in youth associations, proposing a path that started with a self-training in community management in a sustainable key to arrive at imagining the common spaces of their cities as the beating heart for a community development where young people become mentors of the process with a redevelopment of physical spaces in a sustainable key acquiring a managerial awareness in terms of sustainability seen in the round: ecological, economic and social. Participants also discussed the goals of the European Union regarding the Green Deal and the 2030 agenda drafted by the UN, trying to make concrete plans to be able to initiate local sustainable development starting from their localities. All this was done with a self-training path both theoretical and practical made of workshops, meetings and festivals in order to disseminate the reflections that emerged with the community, all with a constant dialogue with institutions and stakeholders, bringing the needs of the communities on the decision-making tables, acquiring the skills necessary to establish communication with local institutions, to map the needs of the community and be able to develop concrete ideas with skills up to the task of maintaining them. This had an impact on the territories, starting from the mapping of needs to the promotion of new methods of active citizenship, for young people able to read needs and know how to respond to them in a sustainable way with solid and wide networks. The goals the project set were: 1.1 to self-train as young citizens and members of youth associations on the issues of green transition in order to make them acquire knowledge about the horizons regarding sustainable development that the European Union intends to achieve and thus beginning to understand what can be in role (as young European citizens) in this process; 1.2 self-training as young citizens and members of youth associations on community development issues, to identify what the role can be in the local process of adapting sustainable development intentions, recognizing themselves as mentors of sustainable community development. To discover this role as a possible and intentional action towards a sustainable community process in order to implement the goals set by the EU White Paper from the European Charter and the 2030 Agenda; 2.1 To carry out needs mapping toward sustainable community development; 2.2 To carry out commons mapping for the promotion of pilot youth participation sites toward green community transition; 3. Leaving a trail. Apply the ideas developed to acquire new skills and participate in the setting up of an area undergoing sustainable redevelopment; 4. Disseminate the practices developed and values promoted in the area; 5. Acquire new managerial skills how to dialogue with institutions and stakeholders and acquire planning skills: how to read needs and know how to implement suitable and sustainable responses.