On 18 May 2010, programmer Laszlo Hanyecz in Jacksonville, Florida, posted on the BitcoinTalk forum: he would pay 10,000 bitcoin for two large pizzas.
The trade
On 22 May 2010 he reported success: "I just want to report that I successfully traded 10,000 bitcoins for pizza." Another user, jercos, ordered the pizzas for him. Laszlo later said they cost about $25, maybe $30 with tip. A forum member estimated the bitcoin were worth about $41 at the time.
Why it matters
It is often cited as the first well-known purchase of physical goods with bitcoin. It showed that a currency with no company behind it could be used to pay for something real – money working as a medium of exchange.
The famous "expensive pizza"
Today 10,000 BTC is worth vastly more. People celebrate 22 May every year as Bitcoin Pizza Day. Without early users willing to spend, though, no one would have known bitcoin could work as money.
Takeaway
Every currency needs a first trade. Bitcoin's was two pizzas.