A public blockchain is a decentralized, open-source network where anyone can participate, validate transactions, and access data. Examples include Bitcoin, Ethereum, and Solana. Public blockchains are trustless and permissionless, promoting transparency and immutability across all users. They rely on consensus mechanisms like Proof of Work or Proof of Stake to secure the network. Public blockchains are commonly used for cryptocurrencies, DeFi platforms, NFTs, and DAOs. They empower individuals with financial sovereignty and enable global collaboration without centralized control or gatekeeping.