What is Bitcoin?
Bitcoin was the first decentralized digital currency and is regarded as the first implementation of a public and decentralized ledger system called a blockchain. To this day, Bitcoin is still the #1 cryptocurrency by market cap, with a peak total value of over $300 Billion USD.
Bitcoin was released in 2009 by 'Satoshi Nakamoto', the pseudonym for the person or people who developed it who are still unknown to this day (although there are many theories).
Bitcoin runs on a Proof of Work algorithm to operate, meaning, among other things, that it is mine-able - Bitcoin users around the world run software and hardware to validate transactions on the blockchain, and are rewarded in Bitcoin for doing so. This process is called mining.