The Bitcoin Genesis block was the first block in the Bitcoin blockchain.
The block header hash for the first block: 000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f
The Genesis block contains a hidden message in the coinbase transaction – it says “"The Times 03/Jan/2009 Chancellor on brink of second bailout for banks" This note from the Satoshi Nakomoto stamped the date of the first block and made a political/economic point regarding the problems with government bailouts of "too big to fail" banks
This is a picture of the Bitcoin Genesis Block