The global "Day of Rage" against the world's financial system won some limited sympathy from political and economic leaders on Sunday, after protests that were peaceful everywhere but Italy.
Cities from east Asia to Europe and north America saw rallies on Saturday denouncing capitalism, inequality and economic crisis, but riot police were busy only in Rome.
The city cleared up on Sunday, a day after masked "Black Bloc" protesters torched cars, attacked banks and hurled rocks.
"They must be condemned by everyone without reservation," Prime Minister Silvio Berlusconi said.
"Yesterday we once again showed the world the anomaly of Italy and today, again, we have to feel shame," La Stampa newspaper said. Mayor Gianni Alemanno said the capital would long suffer the "moral damage" of the rampage.
Many Italians asked why police had managed to arrest only 12 of the violent demonstrators.
Tens of thousands of other "indignant ones" had marched peacefully against the government of deeply-indebted Italy.
On Sunday a small group of peaceful protesters gathered by a church near where some of the violence took place to continue a sit-in. "We are the real indignant ones," one said. "They stole our day."
Lisbon and Madrid also saw tens of thousands march on Saturday. Spanish outrage has been fueled by multi-million-euro payouts for top staff at failed regional banks, amid high unemployment and harsh spending cuts.
But most turnouts worldwide were lower. "People don't want to get involved. They'd rather watch on TV," said Troy Simmons, 47, protesting in New York, where the Occupy Wall Street movement that inspired the global day of unrest began.
In New York a few dozen were arrested for minor offences. Chicago police said they arrested about 175 protesters in a downtown plaza where some had set up tents and sleeping bags. Details of the charges were not immediately available.
Other cities across the United States and Canada saw modestly-sized and peaceful demonstrations.
"I am going to start my life as an adult in debt and that's not fair," student Nathaniel Brown said in Washington.
"Millions of teenagers across the country are going to start their futures in debt, while all of these corporations are getting money fed all the time and none of us can get any."