Closing the HOOP: A Legacy of Circular Innovation The HOOP project, funded under the EU Horizon 2020 programme, supported eight lighthouse cities and regions across Europe in developing large-scale urban circular bioeconomy projects based on biowaste and wastewater valorisation. The project provided tailored Project Development Assistance (PDA) covering regulatory, technical, and financial aspects, and mobilised over €120 million in investments. More than 1,600 stakeholders were engaged through Biowaste Clubs and citizen science, helping build local ownership and shape new value chains. This publication highlights achievements, replicable practices, and strategic recommendations for cities aiming to implement circular economy solutions.