Tezos is a self-amending cryptographic ledger. It achieves consensus not just about the state of a ledger, but about the state of its own protocol. Tezos is a blockchain platform designed to support smart contracts and decentralized applications. Its features include a formal verification system (proof-of-stake), designed to enable a transparent, democratic stakeholder community.
For more on Tezos including pricing and historical insights see: Tezos (XTZ)