Blockchain technology was born in 2008 when Satoshi Nakamoto released the Bitcoin whitepaper. After more than a decade of development, developers have built blockchains with different degrees of decentralization, from high to low: public blockchains, consortium blockchains and private blockchains.
Public blockchains, also known as permissionless blockchains, are the most decentralized and allow all people to send transactions and read information on the chain.
Common public blockchains are Bitcoin, Etherum, Cosmos, EOS, Tron, Nervos, Bitcoin Cash, Litecoin, Kusama, Polkadot, Filecoin, Tezos, etc.