Bitcoin was created in 2008 by the mysterious Satoshi Nakamoto. It is uncertain whether Satoshi was an actual person or a pseudonym for a group of people, and the true identity of Satoshi is unknown to this day. Satoshi wrote a famous paper describing the Bitcoin protocol ( https://bitcoin.org/bitcoin.pdf ) and then released Bitcoin's source in January 2009. Bitcoin began with the genesis block which Satoshi mined himself. After that point Bitcoin began to slowly spread, and by October 2009 the first Bitcoin exchange opened. A Bitcoin exchange is a place where you can buy/sell Bitcoin with fiat. Initially you could buy over 1300 Bitcoins for $1. The price of Bitcoin steadily increased as its use became more widespread, and currently each Bitcoin is worth $620. A famous story from the early days of Bitcoin is that someone bought a $25 pizza for 10,000 Bitcoins. The Bitcoins used to buy that single pizza are worth over $6 million today. Many early adopters of Bitcoin became millionaires, which undoubtedly increased Bitcoin's popularity further.