(CNN) -- The "Occupy Wall Street" movement went global Saturday, crossing the Atlantic to many European cities, where protesters turned out by the thousands for largely peaceful demonstrations. In many cities, handfuls of protesters donned masks portraying a sinister, smiling face with a pointy black mustache and a thin lip beard taken from the movie "V for Vendetta" about a masked hero who fights against totalitarianism.
Here's a country-by-country look at the European demonstrations:
An initially peaceful protest in central Rome turned violent Saturday, after anarchists -- some wearing ski masks and belonging to a group termed "Black Bloc" -- torched cars, broke windows and clashed with police. The violent group also fought with other protesters, who attempted to extricate the rowdy anarchists from the march. Rocks, bottles and tear gas canisters flew, and an interior ministry building caught fire in the mayhem. Firefighters battled the blaze at the main gathering spot, the Piazza San Giovanni, which transformed into a battleground between police with water cannons on the one side and anarchists armed with knives, bats, Molotov cocktails and fireworks on the other, Newsweek correspondent Barbie Nadeau told CNN.
Italy, which was hit hard by the global economic crisis, has been struggling with potentially crippling debt problems. Last month, Standard & Poor's cut Italy's sovereign credit rating, saying the nation's weakening economic growth and political uncertainty have dented its financial stability. Italy has debts equal to nearly 120% of its gross domestic product.
More than 10,000 demonstrators of all ages gathered peacefully in Madrid's spacious Plaza de Cibeles on Saturday and than walked uphill to Puerta del Sol, according to CNN correspondent Al Goodman. The "May 15 Movement" started five months ago to the day over austerity measures and high unemployment. Some demonstrators said they felt Spain's protest had gone global and that the world had joined the movement started in their country. The newspaper El Pais quoted Catalan regional police as saying an estimated 60,000 protesters turned out in Barcelona. CNN was unable to confirm that number Saturday evening.
Along with Italy, Spain was hit by the financial crisis and subsequent European Union debt woes. It announced new measures recently meant to reduce its deficit, though investors continue to believe the country faces dim prospects. Standard & Poor's downgraded Spain's credit rating Friday, citing risks to economic growth and the banking sector.
Spain is one of the so-called "PIIGS," a group of fiscally distressed nations that include Portugal, Italy, Ireland and Greece.
An appearance by Julian Assange highlighted Saturday's "Occupy London" protest, when the WikiLeaks co-founder led the crowd in protest chants from the steps in front of St. Paul's Cathedral on the edge of London's financial district. Thousands marched through the streets protesting austerity cuts and criticizing bankers.
Chancellor of the Exchequer George Osborne told lawmakers in August that the road to economic recovery in Britain will be "longer and harder than had been hoped" and will require continued commitment to the government's deficit-reduction program. He noted that financial instability in Britain's main export markets has contributed to the country's reduced expectations for growth.
About 7,000 people marched through the EU capital of Brussels on Saturday, according to police. "There has been no violence, some people have been stopped and checked but were later released, one has been arrested for assault on a police officer, but apart from that it has been calm," Christianne de Ridder, a spokeswoman for the Brussels police department, told CNN.
Belgium's debt is expected to grow to 85% of GDP by 2015, according to the International Monetary Fund.
Thousands took to the streets in front of the European Central Bank in Frankfurt as well as in other major cities, including the country's capital Berlin, where protesters marched to the Office of the Chancellor. Protesters held up signs condemning corporate power and demanding stronger democracy and social justice.
Germany, the region's economic powerhouse, reported a paltry 0.1% increase in second-quarter gross domestic product, compared with a more robust 1.3% in the first quarter. But economists say Germany is still on track for modest growth in 2011.
The German economy is heavily dependent on exports and has benefited from rapid growth in emerging nations such as China. As activity cools in those markets, the outlook for Germany has dimmed. The slowdown raises troubling questions about the long-term outlook for the Euro Zone.
A small crowd gathered in Stockholm to join the "Occupy" protests. About 400 demonstrators gathered at the central square in Stockholm then "moved on to the Bank of Sweden where they protested some more, and then they went home," a police spokeswoman said. Sweden is known for its strong social democratic system, which provides for many needs of its citizens and protects the stability of Swedish jobs.
Unlike some other members of the European Union, Sweden largely avoided the worldwide recession. Still, the country has a keen interest in helping members of the Euro Zone stay healthy economically. Last year, it offered to loan Ireland $1.5 billion to help it through a tight financial spot. Sweden also depends on the strength of its trading partners, such as Germany, which accounts for some 11% of Sweden's exports and 18% of its imports.
CNN's Per Nyberg contributed to this report