A public blockchain is a decentralized, open network where anyone can join, read, write, or participate in the consensus process. Unlike private or consortium blockchains, public blockchains are fully transparent and permissionless, ensuring trust without relying on a central authority. They use consensus algorithms like Proof of Work (PoW) or Proof of Stake (PoS) to validate transactions and secure the network. Examples include Bitcoin, Ethereum, and Cardano. Public blockchains power cryptocurrencies, decentralized finance (DeFi), and various Web3 applications. Their distributed nature offers high resilience and censorship resistance, though they often face challenges with scalability and energy consumption. Ideal for applications requiring transparency, trustlessness, and open collaboration, public blockchains are foundational to the vision of a decentralized internet.