Bitcoin is a decentralized digital currency, often referred to as a cryptocurrency. It was created in 2009 by an individual or group using the pseudonym Satoshi Nakamoto. Bitcoin operates on a technology called blockchain, which is a distributed and immutable ledger that records all transactions across a network of computers.

Key features of Bitcoin include:

1. **Decentralization:** Bitcoin is not controlled by any central authority like a government or financial institution. It operates on a peer-to-peer network of computers, and transactions are verified by network participants called miners.

2. **Limited Supply:** There will only ever be 21 million bitcoins in existence. This scarcity is coded into the Bitcoin protocol, which aims to mimic the scarcity and value proposition of precious metals like gold.

3. **Anonymity:** Bitcoin transactions can be relatively anonymous, as they are identified by cryptographic addresses rather than personal information. However, the transactions are still recorded on the public blockchain.

4. **Security:** Bitcoin transactions are secured through cryptographic techniques. The network's decentralized nature makes it more resistant to hacking and censorship.

5. **Global Accessibility:** Bitcoin can be sent and received anywhere in the world with an internet connection. This has led to its adoption as a borderless form of currency and a potential alternative to traditional remittance systems.

6. **Volatility:** Bitcoin's value can be highly volatile, leading to both significant price increases and decreases over relatively short periods. This volatility has attracted both investors and speculative traders.

7. **Store of Value and Digital Gold:** Many proponents view Bitcoin as a store of value similar to gold. They argue that its limited supply and decentralized nature make it a potential hedge against traditional financial systems and fiat currencies.

8. **Use Cases:** While Bitcoin's primary use case is as a digital currency, it has also inspired the development of various financial products, services, and technologies, including blockchain applications beyond cryptocurrency.

Bitcoin paved the way for the development of numerous other cryptocurrencies, each with its unique features and use cases. It remains one of the most well-known and widely adopted cryptocurrencies in the world. Keep in mind that the cryptocurrency landscape is constantly evolving, so it's a good idea to consult up-to-date sources for the latest information.