Bitcoin is the first, oldest and most famous cryptocurrency. It was created in 2009 by someone known under the pseudonym Satoshi Nakamoto. The identity of the creator or creators remains unknown. Bitcoin is considered digital gold and a store of value. It's also the largest and most used cryptocurrency in terms of market capitalization. The number of Bitcoins is limited - only 21 million can be extracted. The last Bitcoin will be mined in 2140.