This paper describes Blockchain Integrated Decentralized Urban (BIDU) cities, a radical way for urban environments to function in the next generation of cities via technology. Specifically, BIDU cities will be based on blockchain to allow decentralized, secure, and transparent operations. BIDU cities will not only rely on digital infrastructure but are also tied to civic governance and the delivery of public services. Each aspect of urban life will be interconnected and operate through secured decentralized ledgers. The conceptual architecture of BIDU cities operate with distributed consensus, token economies, smart contracts, and decentralized data transfers. BIDU cities eliminate points of centralized control which allows for empowered citizens, participatory governance, and expanded delivery of services. The paper also considers integration with relevant technologies, including IoT, digital twins, and edge computing, to facilitate real-time data collection and localized decision making. Specific use cases examined include decentralized identity, smart mobility and a blockchain platform, resource optimization in real-time, and urban budgeting to facilitate transparency. Although the authors believe BIDU cities offer a promising development for urban environments, account is given to realized challenges, including interoperability, scalability, compliance and regulations, and the digital divide. Mitigation strategies are discussed including adaptive policies and digitally literate frameworks to be inclusive. In conclusion BIDU cities may foreseeably anchor next-generation urban ecosystems if stakeholders beyond governments come together to adopt those systems on a greater stage.