Bitcoin ($BTC) is the world's first cryptocurrency, created by Satoshi Nakamoto in 2009, based on blockchain technology to achieve a decentralized peer-to-peer payment system. The total supply of Bitcoin is capped at 21 million, giving it scarcity, and it is often regarded as 'digital gold'. It operates without a central authority, with transactions being transparent and immutable, making it popular among investors, institutions, and some countries. Its price is highly volatile, presenting both investment potential and high risk. In recent years, as Bitcoin gradually enters the mainstream financial system through vehicles like ETFs and compliant exchanges, it is evolving from a speculative asset to a global store of value.