The Genesis Block is the very first block in a blockchain. It is the starting point that all subsequent blocks reference. Because each block contains the hash of the block before it, the Genesis Block has no predecessor, its hash is calculated from its own contents and a predetermined nonce. Bitcoin's Genesis Block was mined by Satoshi Nakamoto on January 3, 2009. It contained the text "The Times 03/Jan/2009 Chancellor on brink of second bailout for banks," a reference to a newspaper headline that served as both a timestamp proof and a political statement. The Genesis Block gives a blockchain its immutability. Every entry must trace back to the original block. Rewriting history would require recomputing every subsequent hash, a task that grows exponentially harder with each added block. The Genesis Block is hard-coded into the software, serving as a public anchor that anyone can verify.
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