Bitcoin is a type of digital money that works without banks or governments. It was created in 2009 by someone using the name Satoshi Nakamoto. People can send Bitcoin to each other directly, anywhere in the world, using the internet. All transactions are recorded on a public ledger called the blockchain. Only 21 million Bitcoins will ever exist, making it rare. Some people use it to invest, while others use it to buy things. Bitcoin's price goes up and down a lot, but many believe it's the future of money.