## Transition to Web3 - Course 2 | Blockchain Basics

You might be surprised to see that mining a block isn't that difficult. But then how can the network be safe if the puzzle is so simple? 🤔

**🕵️♀️ Reality check:** Solving the puzzle is actually very difficult. We required that the hash starts with only four zeros just to make it easy for you to mine the block. But for every additional number of zeros we require, the mining difficulty goes up exponentially.

The Bitcoin network adjusts the mining difficulty in a way that takes around 10 minutes to mine a block. Mining difficulty is 40 trillion times more difficult than what it was in 2009! 😵