Ethereum is a decentralized, open-source blockchain platform that allows users to create and deploy decentralized applications (dApps). Ethereum was created in 2015 by Vitalik Buterin and has since become the second largest cryptocurrency platform after Bitcoin. Ethereum allows users to create smart contracts, which are self-executing contracts that are stored on the blockchain and are immutable. For example, a smart contract could be used to facilitate a peer-to-peer transaction, such as buying a car, without the need for a third-party intermediary. The Ethereum blockchain is also used to power decentralized finance (DeFi) applications, which are financial applications that run on the blockchain and are open to anyone.