In May 2010, programmer Laszlo Hanyecz made what would later become one of the most famous purchases in internet history after offering 10,000 Bitcoin to anyone willing to order him two pizzas.

At the time, Bitcoin had almost no mainstream value and was mostly being used by small online communities experimenting with decentralized digital money. Another user accepted the offer, and Hanyecz received two Papa John’s pizzas in exchange for the coins.

What seemed like a completely normal transaction at the time eventually became legendary as Bitcoin’s value exploded in later years. During crypto’s biggest peaks, those same 10,000 Bitcoin would have been worth hundreds of millions of dollars.

The purchase later became known worldwide as “Bitcoin Pizza Day,” a moment still celebrated every year across cryptocurrency communities because it marked one of the first major examples of Bitcoin being used for a real-world purchase instead of existing only as an online experiment.

Ironically, many people now view those pizzas as some of the most expensive meals ever bought.

But without transactions like that, Bitcoin might never have proven it could function as actual money in the first place.