Polkadot is a blockchain protocol designed to support multiple purpose-built blockchains under one unified network. Polkadot’s infrastructure begins with the relay chain, which acts as the central chain. Each chain that runs on Polkadot is called a parachain as they run parallel to the main relay chain, and is built on top of the relay chain. Besides parachains, projects can participate in the Polkadot ecosystem for a shorter fixed period of time through parathreads. Blockchains built on top of Polkadot’s own relay chain are also interoperable with blockchains that have vastly different technology stacks such as Ethereum and Bitcoin through bridges.