# What is the Bitcoin genesis block?

> The Bitcoin genesis block is the very first \block\ of transactions ever confirmed on the Bitcoin blockchain after launching.

> For the complete documentation index, see [llms.txt](/docs/llms.txt).

It's a good time to check out the [Genesis Block](https://blockchain.info/block/000000000019d6689c085ae165831e934ff763ae46a2a6c172b3f1b60a8ce26f) of Bitcoin.

👆🏼 How many properties do you recognize at this point?

The number of **confirmations** is the number of blocks since the genesis block. Since the genesis block is the first block, this is also the **block height** of the blockchain!

It's interesting that if you look at the nonce of the genesis block, it's **2,083,236,893**. If you take a look at a more recent block, [632900](https://www.blockchain.com/btc/block/632900) for example, you'll see that the nonce is actually **much lower**. Why is that? Isn't the difficulty supposed to be getting harder as the network grows? 🤔

It turns out that the block [nonce](https://en.bitcoin.it/wiki/Nonce) is actually a 32-bit field, and `2 ** 32` is **4,294,967,296**, so that is the max size of a nonce. What happens when the miner reaches this point? They can change anything else in the block header to also increase the randomness. Other properties include:

* **Software Version** - Tracks Bitcoin software upgrades
* **Previous Block Hash** - Hash of the block before this one
* **Merkle Root** - We haven't gone over this yet, its a hash that represent all the transactions!
* **Timestamp** - Approximate time (less than two hours in the future according to consensus rules)
* **Target** - Difficulty Target that dictates how small the Proof Of Work must be

👆🏼 As you can imagine by looking at these properties, it was initially the **timestamp** that the miners fiddled with when they needed to restart their search for a valid [Proof-of-Work](/docs/proof-of-work). Beyond that, they can start to change the script of the **coinbase transaction** which gives them additional nonce space.

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