Bitcoin is a digital global currency created in 2009 that allows conducting immediate transactions directly between two persons regardless of their geographic location.  

The central concept of Bitcoin is that there is not a central authority issuing it but instead it is based on a mathematical algorithm and cryptography that cannot be corrupted or altered by anyone, meaning that Bitcoin is safe from the dangers of inflation or devaluation, which is one of the main threats of the fiat money (Fiat).   

The main innovation that makes Bitcoin unique is that it uses a massive consensus using a peer-to-peer network to verify transactions. This results in a system in which payments are irreversible, accounts cannot be frozen and transaction costs are much lower.