Opposition organizers said crowds gathered in around 100 cities and towns across the country despite the Kremlin declaring the protests unauthorized and "illegal" and Russian authorities urging people to stay away.
What were the protests about?
Outwardly the protests appear to be in response to a long-form "investigation" that Navalny and his Anti-Corruption Foundation posted on YouTube. The 50-minute report claims Prime Minister Dmitry Medvedev has assembled "a corruption empire" of luxury properties, yachts and vineyards. Uploaded on March 2, it has since amassed more than 13 million views.
Medvedev's spokeswoman, Natalya Timakova, told state-run news agency RIA Novosti: "It is pointless to comment on the propagandistic outbursts of a convicted opposition figure, who has already announced he is running some kind of election campaign and fighting against the authorities."
What were the rubber ducks about?
CNN saw few protesters carrying posters and signs for fear of being rounded up by authorities immediately, but several waved rubber ducks in the air -- a nod to the allegation that Medvedev has a bespoke duck house at one of his lavish properties.
Others hung old sneakers over trees, a reference to Navalny's corruption probe which highlighted Medvedev's apparent penchant for flashy kicks. The Prime Minister has frequently been pictured at public events in expensive top-of-the-range sneakers.
Protesters also donned green face paint in homage to Navalny, who was attacked last week with green liquid. In the lead-up to Sunday, Navalny had traveled around the country stirring up opposition support but allegedly faced bomb threats and disruptions from supporters of President Vladimir Putin.
The video appears to have galvanized many in Russia who oppose what they see as a corrupt class of political elites living in luxury while ordinary people face financial hardship due to a largely stagnant economy.
According to Transparency International's 2016 Corruption Perceptions Index, Russia is ranked 131 of 174 countries with a score of 29 out of 100. A country's score is based on a 100-point scale, where zero indicates the country's public sector is seen as "highly corrupt," while 100 is perceived to be very clean.
How many took to the streets?
Certainly a lot more than anyone was expecting, with Sunday's crowds believed to be the largest since anti-government protests in 2011.
Unsanctioned demonstrations emerged in multiple cities across Russia including St. Petersburg and Vladivostok, according to local media reports. But the largest gatherings were in Moscow, where state-run news outlet Tass reported that 8,000 people had taken to the streets.
Before the protests were even underway on Sunday, CNN witnessed a heavy police presence -- including riot police and plain-clothes officers -- congregating at a railway station near the city's center arresting opposition supporters as they arrived.
Russian authorities have put the official number of those arrested at 500, but rights groups say between 700 to 1,000 individuals were detained in Moscow alone. Police were seen pushing protesters back on Sunday but CNN did not witness any excessive use of force.
How did the Kremlin respond?
Initially, with silence. State media appeared to implement a blackout which ignored the ongoing protests on Sunday.
When asked about the lack of television reporting, Kremlin spokesman Dmitri Peskov denied restricting coverage during his regular morning conference call with journalists on Monday.
"We don't create the editorial policies of TV channels. TV channels show what they think is important ... there are just so many ways to get information, so it's not right to say that the information is restricted in any way," Peskov said.
In the same call, Peskov condemned the "illegal" marches, pointing out that protest coordinators had been offered two alternative places to hold demonstrations, but that both had been rejected. Opposition organizers said that the routes offered were not in Moscow.
The Moscow Police Department put out a statement Thursday urging people not to attend, calling it illegal and warning of a high risk of "provocative acts, designed to violate public order."
What did the Kremlin say about young people?
Peskov also claimed there was a high number of young people involved in the demonstrations because they had been offered financial incentives to be there.
He said: "We cannot respect people who knowingly mislead the underage kids, in fact, asking them, while promising some sort of rewards, to participate in an illegal event."
Are we headed towards an electoral upset?
It's highly unlikely. Navalny has announced his intention to run for the presidency in 2018, but Russian law prevents convicted criminals from running for public office.
Navalny was jailed for 15 days on Monday over his role in the mass protests Sunday.
Last month, Navalny was convicted of embezzlement in a retrial of a case that dates back to 2013. He is serving a suspended sentence, but has appealed the verdict.
Russia's state-run news agency Tass has reported that the suspended sentence could be replaced by a real jail term as a result of Monday's convictions.
Russia's opposition has been fighting an uphill battle for years. Much of the country's independent media has been shuttered or nationalized, and as a result, those railing against the Kremlin have struggled to find a platform to gain real traction with voters.
Opposition figures have also had to contend with harassment and prison time, as Navalny and business magnate Mikhail Khodorkovsky have found.
Some top Kremlin critics have even turned up dead, including Boris Nemtsov, who was gunned down in Moscow in 2015.
On Thursday, a former Russian lawmaker and vocal critic of the Russian government, Denis Voronenkov, was shot dead outside a luxury hotel in the Ukrainian capital Kiev.
What does this mean for Putin?
Very little. The protests were ostensibly against corruption and it's doubtful that they will pose any significant threat to Putin, who boasts approval ratings around 80%.
What it does show is a willingness by the opposition populous to hit the streets regardless of whether authorities allow them to or not.
And the demonstrations will not please Putin, particularly as they come just two weeks after the 100-year anniversary of the revolution that ousted Russia's last tsar.