This podcast episode explores the technical details, security, scalability, phased rollout, vision, interoperability, and future roadmap of Build on Bitcoin (BOB), a hybrid blockchain that combines Ethereum and Bitcoin. BOB enables seamless bridging of assets between Bitcoin and Ethereum networks, simplifying the on-ramping process for users. The security of BOB depends on Ethereum in its initial phase and incorporates Bitcoin security through merged mining in phase two. The phased rollout plan aims to gradually increase decentralization and ensure the best possible security for both Bitcoin and Ethereum users. BOB also aims to provide the infrastructure for a financial system running on Bitcoin, offering decentralized financial applications and interoperability between EVM-based chains. The Spiderchain, a decentralized Layer 2 solution, enhances the security and scalability of BOB, while Citrea, a zk-rollup on Bitcoin, aims to enable a Bitcoin-backed economy with minimized trust assumptions. The future roadmap includes trustless zk-rollups and attracting developers and liquidity to the platform, ultimately enhancing the security and user experience of Bitcoin-backed stablecoins.