Bitcoin is a decentralized digital currency created in 2009 by an unknown person or group using the pseudonym Satoshi Nakamoto. It operates on blockchain technology, a secure and transparent ledger maintained by a network of computers called nodes. Bitcoin allows peer-to-peer transactions without intermediaries like banks, offering low fees and global accessibility. Its supply is capped at 21 million coins, making it scarce and often viewed as "digital gold." Bitcoin is used for payments, investments, and as a hedge against inflation, but it is highly volatile and often criticized for energy consumption and potential use in illicit activities.