A public blockchain is a decentralized, open-source network that anyone can access, use, and contribute to. It operates without a central authority, making it more transparent and secure. Public blockchains, like Bitcoin and Ethereum, allow users to participate in the validation process through mining or staking. These blockchains are resistant to censorship and offer transparency in transactions, making them ideal for cryptocurrencies, decentralized applications (dApps), and smart contracts. With high levels of decentralization, public blockchains foster trust and ensure that data remains immutable and accessible to all participants on the network.