Genesis

Monero has a hardcoded genesis block that gets added to the blockchain on the first run of the daemon¹. The contents of this block are different depending on the network.

For all networks the timestamp is set to 0, the major and minor version of the block are set to CURRENT_BLOCK_MAJOR_VERSION and CURRENT_BLOCK_MINOR_VERSION², These two constants are set to 1 and 0 respectively³. The transaction field is empty, and the previous block hash is not set so that field is zeroed.

Mainnet

The nonce is set to 10,000 and the miner transaction is set to: 013c01ff0001ffffffffffff03029b2e4c0281c0b02e7c53291a94d1d0cbff8883f8024f5142ee494ffbbd08807121017767aafcde9be00dcfd098715ebcf7f410daebc582fda69d24a28e9d0bc890d1 ⁴

The mainnet genesis block will hash to: 418015bb9ae982a1975da7d79277c2705727a56894ba0fb246adaabb1f4632e3.

The final block:

{
    header: {
        major_version: 1,
        minor_version: 0,
        timestamp: 0,
        previous: [0; 32],
        nonce: 10000
        },
    miner_tx: "013c01ff0001ffffffffffff03029b2e4c0281c0b02e7c53291a94d1d0cbff8883f8024f5142ee494ffbbd08807121017767aafcde9be00dcfd098715ebcf7f410daebc582fda69d24a28e9d0bc890d1",
    txs: [],
}

Testnet

The nonce is set to 10,001 and the miner transaction is set to the same as mainnet⁵

The testnet genesis block will hash to 48ca7cd3c8de5b6a4d53d2861fbdaedca141553559f9be9520068053cda8430b.

The final block:

{
    header: {
        major_version: 1,
        minor_version: 0,
        timestamp: 0,
        previous: [0; 32],
        nonce: 10001
        },
    miner_tx: "013c01ff0001ffffffffffff03029b2e4c0281c0b02e7c53291a94d1d0cbff8883f8024f5142ee494ffbbd08807121017767aafcde9be00dcfd098715ebcf7f410daebc582fda69d24a28e9d0bc890d1",
    txs: [],
}

Stagenet

The nonce is set to 10,002 and the miner transaction is set to: 013c01ff0001ffffffffffff0302df5d56da0c7d643ddd1ce61901c7bdc5fb1738bfe39fbe69c28a3a7032729c0f2101168d0c4ca86fb55a4cf6a36d31431be1c53a3bd7411bb24e8832410289fa6f3b ⁶.

The stagenet genesis block will hash to 76ee3cc98646292206cd3e86f74d88b4dcc1d937088645e9b0cbca84b7ce74eb.

The final block:

{
    header: {
        major_version: 1,
        minor_version: 0,
        timestamp: 0,
        previous: [0; 32],
        nonce: 10002
        },
    miner_tx: "013c01ff0001ffffffffffff0302df5d56da0c7d643ddd1ce61901c7bdc5fb1738bfe39fbe69c28a3a7032729c0f2101168d0c4ca86fb55a4cf6a36d31431be1c53a3bd7411bb24e8832410289fa6f3b",
    txs: [],
}