From January 2002, millions of people across Europe will queue at their banks and post offices to get hold of the new money, while cash points and teller machines are being converted to handle the euro. Most of the coins will be brought into circulation through retailers, who will give euro change to bills settled in national currencies. Introducing the new money is a logistical nightmare - and a huge security problem. Billions of notes and coins have to be kept safe, and then safely distributed to shops and banks across the eurozone.
Coins are the biggest problem.
But the ECB had a chance to learn the lessons of a previous switch from one currency to the other, when in 1990 East Germany dumped its currency for the West German Deutschmark, shortly before the reunification of the two countries.