ClimaGen will demonstrate how Climate-resilient regeneration and renaturing for, by and with vulnerable neighbourhoods, can help cities and regions in their transitions towards net-zero. 5 Demonstration cities (Belgrade, Gdańsk, Tartu, Torino, and Trondheim), will implement 25% increased share of newly created and/or restored public green spaces in each city. 4 Replication Cities (Cluj-Napoca, Eindhoven, Gernika and Thessaloniki) will experiment with shorter-term co-creative measures with the same objectives and methods to plan for future implementation of the measures. All 9 cities will run their own Work Packages in ClimaGen, supported by 5 cross-cutting concepts and 4 transversal WPs: ClimaGreens will nurture integrated renaturing measures that create resilience at several scales, and avoid maladaptation in the journey to climate-neutrality. ClimaLabs will provide local and regional collaborative governance, with arts, culture and youth, entrepreneurship and financing, and organisational resilience in long-term planning strategies. ClimaImpact will generate evidence-based decision support and valuation of co-benefits, in easy-to-understand and, where possible, visualised formats. ClimaValue will offer outreach, capacity building and policy guidance, with strategic advocacy together with sister projects and close collaboration with Missions/NEB communities, while an evidence-based ClimaGen Guidance Package will disseminate results and knowledge to cities. City Dialogues and cross-cutting Sense-Making Sessions will support local implementation and common learning. Together these define impact pathways to knowledge sharing, scaling and replication. The ClimaGen Games will tie these activities together with a portfolio of participatory, gamified, citizen-science-based methods to engage all partners and stakeholders in an inclusive manner, and to use their diversity as a strength.