From the Arctic Sea to the Straits of Gibraltar, European police are on high alert as armored vans and military convoys carry hundreds of billions of dollars' worth of Europe's new currency to shops and banks across the continent.
With less than a month to go before 12 countries ditch their traditional money and start using the euro Jan. 1, "the most important problem we face right now is armed robbery," says Christian Jacquier, head of the financial crimes unit at Europol, the pan-European police intelligence unit.
Only one heist has been reported so far, when a German bullion truck driver made off with $1.2 million of the new currency.
Governments have coped with the threat by storing euros in military barracks and sometimes transporting them in military vehicles. But the authorities are on the alert for other criminal attempts to take advantage of the biggest financial transaction in history - the conversion of 600 billion dollars' worth of old money into new.
As shopkeepers got their hands on the first euros this week, Europol had not seen any counterfeit notes, says Mr. Jacquier, although he is sure they will turn up soon enough, given that the euro is intended to be a world currency in a league with the US dollar.
The European Central Bank has made life harder for forgers by releasing the notes only this week, and by manufacturing what it claims are the most counterfeit-proof banknotes ever made, with security features ranging from watermarks and holograms to metal strips and ink that changes color depending on the light.
Critics have warned that the new currency, especially its top-value 500 euro note (US$450), will be a boon to money launderers and money smugglers wanting to transport large sums of ill-gotten gains easily. But the authorities say they expect no significant increase in money laundering; they think the currency will instead pose difficulties for criminals.
"Most criminals buy things with the fruits of their crime and don't use banks," says Jacquier. "The euro will be a problem for them because they will have to go through the banking system one way or another to get the new currency, which is an opportunity for us to track them."
Banks must report anyone changing more than 10,000 euros (US$9,000) in cash from an old currency into the new one.
Though most European citizens see the currency switch as a chore at best, full of opportunities for fraudsters and dishonest shopkeepers to take advantage of public confusion over how much the euro is worth, some are seeing it in a more positive light.
Esther Jacobs, for example, is hoping to turn useless old coins that her Dutch compatriots have left lying around in forgotten corners into more than $20 million for charity.
Though shoppers will be able to use their old national coins and notes for six weeks after the switch, there is nothing they can do with foreign coins that they have left over from past holidays or business trips.
"People don't throw money away," says Ms. Jacobs, a marketing consultant who says she launched her charity drive "so as to do something right for once, to create something positive out of something negative."
So Ms. Jacobs's "Coins for Care" organization is encouraging people to throw their coins into 10,000 collecting boxes set up in shops, gas stations, and banks across the country, or to hand them over during a massive door-to-door campaign that will visit every household in Holland next month.
"We are asking people to give away something that is of no more value to them, it's like collecting scrap iron," says Jacobs, whose initiative has sparked similar efforts in Belgium, Austria, and Germany.
The coins will then be sorted and sent back to the central banks that originally issued them, which will pay euros for them.
Meanwhile, ordinary citizens are being bombarded with information helping them prepare for the changeover. Using the slogan "The euro, our money," TV spots advertising hoardings, brochures, posters, and leaflets are hammering home the message about the eight new coins and seven new banknotes that Europeans will be using in less than four weeks' time.
In France, cable Internet providers are posting helpful hints about the changeover on their home pages; in Portugal priests have been enlisted to spread the word in poor rural areas where older people still think in reals, a currency that has not existed for a hundred years.
Opinion polls show that different countries are in different states of readiness - the Finns the best informed, the Greeks the worst. And of course the changeover will be easier for some than for others. Germans will simply have to halve the price of a euro to work out its rough equivalent in familiar deutsche marks, the poor Austrians will have to divide by 13, and Italians - who are used to paying thousands of lire for anything more expensive than a cup of coffee - will find it difficult to get used to decimal points.
But overall, the European Central Bank that is overseeing the currency switch, and national governments who are implementing it, appear to be cautiously confident that the experiment will work.
"For a while, we will all feel abroad in our own countries," predicts Jerome Lagarde, who wrote a booklet of euro tips that the French authorities have handed out to confused citizens. "It will be good for us."
Not that the changeover is expected to be completely trouble-free.
Pascale Lanterne, who runs a small family bakery in central Paris, had hoped to pick up her first euro coins from the bank this week, but she was disappointed. The bank didn't have any because the mint hadn't delivered them.
"I think they are a bit overwhelmed," says Ms. Lanterne. "I'll have to wait."
And in Lisbon, Portugal, Jonas, an elephant at the Lisbon Zoo, has been taught to take Portuguese coins with his trunk. But he only accepts coins 20 escudos and higher. He will now have to distinguish the new euro coins.