For the first time since the era of the Roman Empire, all of Europe is using one currency — in this case, rainbow-colored bank notes called euros. 

After midnight struck and New Year's Day dawned, people across the continent began trying to use the novel money. But since so many cafes, restaurants and shops were closed Tuesday for the holiday, patrons found themselves sticking to their old currency.

Most Europeans saw the crisp, new bills for the first time on the way home from New Year parties, when they stopped at automated teller machines. Others who went out to breakfast and paid with their old currency got their change in Euros.

"It's funny to pay in francs and get this back," said Evelyne Patou, a customer in a Paris bakery, examining a pastel blue bank note. "It's like Monopoly money."

After more than a decade of preparing for the one-currency system, the euro became legal tender in the continent on the first of the year 2002.

It is perhaps the most concrete evidence of Europe's transition from a divided continent to a team of nations working toward the same goals.

The 12 European Union nations that adopted the euro are parting with currencies that have long histories — such as Greece's drachma, which stretches back 2,600 years.

Things seemed to be going smoothly for the infant currency on its first day in existence.

Emad Kolta, 49, who runs a newsstand in a subway station in Vienna, said he didn't feel completely prepared yet for the switch — but that so far, he had been able handle it, even though he had no euros to use as change.

"I thought this morning, if I come to work and have problems with the euro I'll just close the shop and open it back up tomorrow. But so far, I've had no problems," he said.

Reaction to the euro varied by country. In Belgium, people were eager to get their hands on the new money — ATMs had a record number of withdrawals from midnight to 1 a.m. Tuesday, 600 a minute. In Finland, hundreds of people lined up outside Bank of Finland branches in the early morning.

In laid-back Spain, 85 percent of ATM machines were dispensing euros by Tuesday afternoon, but people weren't rushing out to spend them. Some bars, coffee shops and restaurants in Madrid even shunned euros, albeit politely, saying they had no coins or bills to make change. Cafes in Rome, Paris and Vienna also said most of their clients paid with the old currencies.

In Italy, only about a third of ATMs were dispensing euros, according to the Italian Bankers Association.

The real test will come Wednesday, when the work week starts. To complicate matters, bank workers in Italy and France were expected to go on strike on Wednesday, pressuring management at a difficult time.

More than 15 billion bank notes and 52 billion coins — worth 646 billion euros, or $568 billion — have been produced for the switch. Depending on the country, people have up to two months to get used to their new currency while the old one is phased out.

During the transition, shopkeepers have devised ways to keep two different currencies straight. Some bakeries in Paris, for example, set up two separate cash registers — one for euros, one for francs. Some taxi drivers used two separate pouches to keep their change straight.

Even though officials urged people to use change for their purchases, many used large euro bills at cafes and newsstands — draining some shops of small bills and coins.

"I have only a little change," admitted Fabio Moschini, a cashier in a Roman bar, pointing to the 15 euro coins in his register. "I am afraid this week might be difficult."

To keep long lines moving, staff at the Eiffel Tower decided to accept only one currency — the euro — and directed visitors to a currency change stand under the tower's arching metal legs. Many visitors were annoyed.

"Why can't they have both?" said Sarah Wheatley, from Kent, Britain, who couldn't get hold of euros when she was preparing for her trip. Britain, Sweden and Denmark are the only EU countries that have not adopted the new currency.

In an interview in Vienna with The Associated Press, European Union Commission President Romano Prodi predicted the euro's debut would create a feeling of community that comes "from having the euro in your pocket."

Pope John Paul II also saluted the euro's arrival at a New Year's Day Mass, offering "a special wish for peace and prosperity to the nations of the European Union that, today with the single currency, accomplish a historical goal."

While some leaders mused on European unity, others went on euro-shopping trips and called in the camera crews. German Chancellor Gerhard Schroeder bought some bananas, while French Prime Minister Lionel Jospin bought a bottle of Burgundy wine, croissants and a bouquet of flowers for his wife.

The Associated Press contributed to this report.