– The scale of Russia’s nationwide protests last weekend took even their organizers by surprise.

Tens of thousands of Russians took part in anti-corruption demonstrations from west to east across 82 cities. In Moscow, the protest culminated in more than 1,000 arrests — a record for the city under Vladimir Putin’s rule.

The man who brought the country out into the streets was only able to revel in his achievement for a few brief minutes: As soon as opposition leader Alexei Navalny appeared on Moscow’s central Tverskaya Avenue, he was detained by police. (The next day, a Moscow court fined Navalny $350 for organizing banned protests and sentenced him to 15 days in jail.) But Navalny remained defiant: “The time will come when we will have them on trial (but honestly)” he tweeted.

Two weeks earlier, Navalny — Putin’s most prominent critic, and the one most devoted to opposing him at the ballot box — had published an investigation into Prime Minister Dmitry Medvedev’s alleged corruption. His team released a video revealing that Medvedev had amassed a collection of palaces, yachts and vineyards during his time in office. Navalny’s Anti-Corruption Foundation regularly publishes blogs and videos making public the ill-begotten riches of people within or close to the government: past exposés have focused on the business empire belonging to the son of Russia’s general prosecutor and the millions allocated to a foundation run by Putin’s daughter. With the Medvedev video, however, Navalny managed to strike a nerve like never before.

Russia is now in its third year of a serious economic recession and has been living under Western sanctions since annexing Crimea from Ukraine in 2014. The news of Medvedev’s secret fortunes at a time of nationwide suffering had the country furious. In a matter of days, millions of Russians had watched the video on YouTube.

The prime minister’s riches quickly became a symbol of all the injustices in Putin’s Russia, where corruption is part of daily life. According to Navalny, Medvedev used a web of charities run by his associates to conceal his fortunes. “Dimon (Medvedev) Will Answer” became the protest’s slogan; Russians carried banners of ducks, alluding to the expensive home Medvedev allegedly built for water fowl on a pond on one of his estates, and sneakers around their necks, representing his expensive shoe collection.

It wasn’t just the ostentatious wealth that had protesters so angry, however. Medvedev, who served as president between 2008 and 2012 before Putin returned to the presidency, has long been an unpopular figure.

Unlike Putin, who never appears in a compromising light, Medvedev is the Kremlin official most prone to gaffes. He is famously tone deaf: On a trip to Russian-annexed Crimea last year, he famously told a group of angry pensioners: “There’s no money — but you hang in there!” The quote immediately went viral. (His reaction to the protests against him was true to form: An Instagram user asked the prime minister, on his page, how his day went. Medvedev replied: “Not bad, I went skiing!”)

While Putin’s approval ­ratings have soared as a result of his efforts to play tough with the West and secure military victories abroad, Medvedev has taken the blame for the economy. For the past few years, the Russian public, and even some within Putin’s hard line inner circle, have considered Medvedev both weak and dispensable.

And so, it was only a matter of time before Navalny — a savvy operator who recently announced plans to run for the presidency next year — saw an opening.

By focusing his protests on Medvedev, analysts say, Navalny managed to get turnout on a scale that he’d never achieved before. That’s in part because the framing appealed to two very different groups: the politically discontented in Moscow and St. Petersburg, and those living in Russia’s far-flung regions, where protest movements have traditionally had little appeal.

Most Russians far from the cities would think twice before protesting their president, but they care little for his clumsy prime minister. They also witness the painful effects of localized corruption on a daily basis. It was these regional protests that took Russian authorities most by surprise.

“Protests took place not only in regional hubs but in even smaller towns — this has never happened before,” said Russian political commentator Alexander Kynev. In some cases, there were protests in small provincial cities like Biysk, in Russia’s far east Altai Krai region, which hadn’t seen people protesting on the streets on a large scale since the 1990s.

Moscow-based politicians are usually viewed with skepticism and disdain in Russia’s isolated provinces. In Putin’s Russia, the important decisions are taken in Moscow; regional authorities are mere executors, and standards of living in regional hubs are far lower than in the glossy capital. But Navalny has managed to make some surprising inroads into far-flung places.

Last month, Navalny began a tour around Siberia and the Volga region. He spoke at a protest against housing tax hikes in Siberia’s Novosibirsk. The following week he was in Volgograd, where he promised to investigate the ­financing of mansions belonging to local officials. While he was there, an unknown man threw green ink on his face as part of a smear campaign; Navalny took the attack in stride, and on Sunday, some protesters painted their faces green in solidarity.

“He has very successfully exploited the incompetence of local officials in the regions,” says Konstantin Kostin, head of Moscow’s Foundation for Civil Development. This unlikely success is unsettling for the Kremlin, which has tolerated Navalny mobilizing middle-class Muscovites but may feel differently if he starts winning followers among Putin’s traditional electorate.

Choosing Medvedev as a target may have also helped Navalny boost turnout among another unlikely group: teenagers. The protests saw few veterans of the 2011-2012 demonstrations. The faces in the crowds were much younger. Many of the Russians protesting were born after the fall of the Soviet Union in 1991, and some even after Putin came to power in 2000.

The high number of Russian teens involved in the protests has raised questions about whether the generation now coming of age in Putin’s Russia is prepared to live under the same rules as their parents.

This generation of Russians does not watch TV, the news source most dominated by Putin propaganda, analysts say. Instead, they rely mostly on social media, over which the Kremlin exercises much less control.

Come next year’s presidential election, many of the young people who took to the streets on Sunday will be of voting age. And on Monday, still reeling from having been caught off guard, the government may have made a misstep that alienated young people still further: Putin’s spokesman suggested that young people had been bribed into protesting.

Meanwhile, state-controlled TV chose to ignore the protests, focusing instead on the standoff between Russia and Ukraine ahead of this year’s Eurovision song contest. But online, thousands of videos of crowds are making the rounds on Russian social media. “This is far from a political crisis,” said political analyst Mikhail Vinogradov, “but it is a very inconvenient situation.”