Tr3zor presents a sustainable solution to the problem of finding lost or stolen belongings through the utilization of blockchain technology and the implementation of multiple incentive mechanisms. We a global, blockchain-based online platform for lost and found belongings that can also act as a digital Tresor. The platform offers a high degree of security & transparency, forgery-proof logs, advanced functionality that enhances the user experience, incentive mechanisms such as bounties and a comprehensive gamification system as well as other features that are otherwise not available with traditional platforms, apps, and government agencies like lost and found offices. Tr3zor creates an interconnected, cooperative network between multiple entities and places where people most frequently lose their belongings. We are establishing connections with lost and found offices in cities and at airports, the police, hotels, public transport companies, restaurants, railway and bus stations and many others. This ensures that the network has the highest reach possible even beyond the community-based model, increasing the likelihood of a property getting found by its owner and thus the incentive for more people to join, resulting in a continuous accumulation of new users and, eventually, widespread international adoption.