Bitcoin is not just a cryptocurrency, but also a new financial system comprised of many components. It was invented in 2008 by the mysterious Satoshi Nakamoto and released shortly after the public. Most importantly, Bitcoin is not controlled or owned by any individual, corporation, or government. It extensively uses cryptography and relies on a peer-to-peer network.
Bitcoins derive their value party through their scarcity, which is defined by a cryptographic lottery. You can either buy Bitcoins on online cryptocurrency exchanges or you can earn them through a process known as mining.