The synergistic relationship between 6G and blockchain, showcasing how their integration supports secure, real-time data exchange and robust smart city operations are examined. Practical applications such as smart traffic management, energy-efficient buildings, secure digital identities, and decentralized governance are analyzed through real-world case studies, highlighting successes and challenges. This chapter also addresses technological, regulatory, and societal challenges to the widespread adoption of these technologies, including interoperability, scalability, and privacy concerns. Prospects are explored, considering the role of emerging technologies like AI, IoT, and quantum computing in enhancing smart city development. By providing a comprehensive analysis, this chapter offers valuable insights for policymakers, urban planners, technologists, and researchers dedicated to building the smart cities of tomorrow.