Bitcoin is a cryptocurrency and peer-to-peer payment system that was created in 2009. It allows users to send money to each other without going through a bank. Transactions are recorded on a public ledger called the blockchain. There are now hundreds of other cryptocurrencies besides Bitcoin. Blockchains are distributed ledgers that record transactions immutably across a network of computers. Cryptocurrencies and blockchains have several potential use cases, such as providing financial access in Venezuela and for refugees. Government agencies are also exploring blockchain applications. Blockchains are not suitable for all uses and do not replace the need for trust between parties in some cases.