The euro, the common currency that links 19 countries, has now been around for 21 years.
The euro first replaced 12 national currencies when it was introduced as coins and banknotes on January 1 2002. The what the european Union describes it as the "biggest cash changeover in history."
But the currency was actually first introduced in 1999, when it was used for things like online payments, giving millions of people time to prepare.
Its introduction had been a goal for many European countries for decades. Now, around 341 million people use it every day, according to the EU, this makes it "the second most-used currency worldwide."
Not every one of the 28 countries in the EU uses the euro. The UK, for example, continues to use its pound. The countries that use the currency are collectively called the Eurozone — and other countries outside the EU, like the Vatican, also use it, while other EU countries are looking to adopt it.
Here are the currencies the euro it replaced when it was first introduced:
The German Mark was seen as one of the world's most stable currencies when it was in circulation, and it played a role in the reunification of the country after WWII.
Around 1.96 Marks was worth one euro.
It ceased to be accepted immediately after the euro was adopted. This contrasted with most European countries, where there was a period where people could pay with both the old currency and the euro.
People across Europe queued at banks in 2002 to get the new money, and the old was destroyed by central banks. Many old currencies can still be exchanged for Euros.
One euro was worth around 2.2 Guilders. The notes were considered some of the world's most beautiful.
One euro was more than 1,900 Lire.
One euro was worth around 166 Pesetas.
Around 6.6 Francs was worth one euro.
Punt means pound in the Irish language, but the currency was entirely distinct from the UK pound.
The coin design was striking and simple, highlighting the country's wildlife.
One euro was worth around 0.78 Punts.
The Schilling was in place before and after WWII, though it was replaced during the war by the Reischmark as Germany annexed the country.
One euro was worth around 13.8 Schillings.
Greece actually didn't introduce the euro in 1999 like the other countries, but introduced it in time for the 2002 adoption.
The Drachma has roots in ancient Greek, and 340.75 of them were worth one euro.
The currency was distinct from the French Franc.
Just over 40 Luxembourg Francs were worth one euro.
One euro was worth around 200.5 Escudos.
The Markka replaced the Russian Ruble after Finland gained independence from the USSR.
5.9 Markkas were worth one euro.
The Belgian Franc was also independent from the French Franc.
Around 40 Francs were worth one euro.
See the latest EUR-USD movements here.
ncG1vNJzZmivp6x7o8HSoqWeq6Oeu7S1w56pZ5ufonyntdGsq2adpae8sbHAp2ScraKnsq%2BvyJ6qZqqVpbmir8SdZJuxXZrCs7uMa2draF1m