Cryptocurrencies are digital currencies that use cryptography to ensure secure and decentralized transactions. They operate through a technology called blockchain, which records each operation on a distributed network. Bitcoin was the first cryptocurrency, launched in 2009, and since then thousands of alternatives have emerged such as Ethereum, Solana, and Cardano. Many people invest in cryptocurrencies seeking high returns, although their value can be very volatile. In addition to serving as investment assets, some cryptocurrencies allow for executing smart contracts or making fast international payments with low fees. Despite their growth, they face regulatory challenges and concerns about security and sustainability.$BTC