It's a sight Russia hasn't seen for 20 years - a mass anti-government demonstration that's been allowed to go ahead.
Tens of thousands of Muscovites thronged to a city square to protest against alleged electoral fraud and against Russian Prime Minister Vladimir Putin and his party on Saturday, and demonstrators gathered in other rallies across the vast country, the largest public show of discontent in post-Soviet Russia.
CBS News correspondent Charlie D'Agata reports there have been clashes in St. Petersburg, with riot police dragging away protesters. Demonstrations in Moscow have so far been peaceful but they are growing in number and anger.
More than 10,000 people packed Moscow streets near the Kremlin, with more arriving by the minute.
Opposition parties say 30,000 people will take part in protests in Moscow alone, and thousands more in cities across the country.
"Everyone is sick of living under this regime which forbids freedom of expression," one demonstrator told CBS News. "We are against the lies and the bankrupt politicians."
There have been some comparisons between the Arab Spring and now the Russian Winter, but those uprisings took hold after days of protests. That, said D'Agata, is not something Putin and his security forces are likely to tolerate.
The protests come three months before Putin, who was president in 2000-2008 and effectively remained the country's leader while prime minister, is to seek a third term in office. The public outpouring challenges his image, supported by state-controlled TV channels, as a man who won the affection of most Russians.
That image was undercut by last Sunday's parliamentary elections, during which his United Party narrowly retained a majority of seats, but lost the unassailable two-thirds majority it held in the previous parliament. Even that reduced performance was unearned, inflated by massive vote fraud, the opposition says, citing reports by local and international monitors of widespread violations. The reports of vote-rigging and the party's loss of seats acted as a catalyst for long-simmering discontent of many Russians.
"The falsifications that authorities are doing today have turned the country into a big theater, with clowns like in a circus," said Alexander Trofimov, one of the early arrivals for the protest at Bolotnaya Square, on an island in the Moscow River adjacent to the Kremlin.
"I don't think any citizen of the country can say he is very happy with anything. We don't have an independent judiciary, there is no freedom of expression all this combined creates a situation where people are forced to protest," said demonstrator Albert Yusupov, who was dressed in civilian clothes but identified himself as a member of the Russian army.
By the time the rally started, the square and adjacent streets were packed shoulder-to-shoulder with protesters braving intermittent wind-blown snow. Police said there were at least 25,000, while protest organizers claimed 40,000.
City authorities have given permission for a rally of up to 30,000 people, unusual largesse for an opposition that generally is either denied permission to rally or limited to small numbers. It was not clear if police would choose to crack down if the crowd clearly exceeded 30,000. But they did try to move demonstrators off a footbridge leading to the island, claiming it was so packed with people that it could collapse.
Protests took place in at least 15 other cities from the Pacific Coast to the southwest.
In the Pacific city of Vladivostok, several hundred protesters rallied along a waterside avenue where some of Russia's Pacific Fleet warships are docked. They shouted "Putin's a louse" and some held a banner caricaturing United Russia's emblem, reading "The rats must go."
Police stayed on the fringes of that demonstration and made no arrests. But the Interfax news agency reported that about 15 people were arrested at a protest in the Siberian city of Perm and about 30 in the Far Eastern city of Khabarovsk when a flash-mob started an unauthorized protest.
Officials in many cities, including Moscow, gave permission for the protests. But in what appeared to be an attempt to prevent young people from attending the protest, Moscow's school system declared Saturday afternoon a mandatory extra school day for grades 9-11. Students were told of the decision only on Friday, news reports said.
Hundreds of people, were arrested in smaller protests earlier in the week. Some, including prominent opposition blogger Alexei Navalny, were sentenced to 15 days in jail. Another prominent opposition figure, Sergei Udaltsov, was hospitalized after his Monday arrest and was expected to be released Saturday, but the Interfax news agency said he was taken from the hospital to a court to face further charges.
Russian President Dmitry Medvedev conceded this week that election law may have been violated and Putin suggested "dialogue with the opposition-minded" breaking from his usual authoritarian image. The Kremlin has come under strong international pressure, with U.S. Secretary of State Hillary Clinton calling the vote unfair and urging an investigation into fraud. Putin in turn criticized Clinton and the United States for allegedly instigating protests and trying to undermine Russia.
If Saturday's protests are a success, the activists then face the challenge of long-term strategy. Even though U.S. Sen. John McCain recently tweeted to Putin that "the Arab Spring is coming to a neighborhood near you," things in Russia are not that simple.
The popular uprisings that brought down governments in Georgia in 2003, in Ukraine the next year, and in Egypt last spring all were significantly boosted by demonstrators being able to establish round-the-clock presences, notably in Cairo's Tahrir Square and the massive tent camp on Kiev's main avenue. Russian police would hardly tolerate anything similar.
Opposition figures indicated Friday that the next step would be to call another protest in Moscow for next weekend and make it even bigger. But staged events at regular intervals may be less effective than daily spontaneous protests.
Russia's opposition also is vulnerable to attacks on the websites and social media that have nourished the protests. This week, an official of Vkontakte, a Russian version of Facebook, reported pressure from the FSB, the KGB's main successor, to block access to opposition groups, but said his company refused.
On election day, the websites of a main independent radio station and the country's only independent election-monitoring group fell victim to denial-of-service hacker attacks.