Polkadot (DOT) is a blockchain network that connects many specialised blockchains so they can share data and security. It was founded by Gavin Wood, a co-founder of Ethereum, and launched in 2020 with the Web3 Foundation. Instead of a single chain, Polkadot uses a central Relay Chain that provides shared security, with independent chains called parachains plugging into it. This lets developers build chains for specific uses while still communicating with each other. DOT holders can vote on network upgrades, stake to help secure the Relay Chain, and use DOT to pay for access to network resources.