Outraged Polish women said it with umbrellas, locked-down Serbians banged pots from open windows and environmentalists did what they have always done - climbed a tree.
But as they struggle to rekindle the spirit of protest in the age of coronavirus, despite lockdowns or bans on public gatherings, most demonstrators have sought to obey social-distancing rules.
Measures to stop contagion have stifled protest movements worldwide, from the mass demonstrations of Hong Kong to the civil disobedience of climate activists in London who last year caused gridlock by shutting roads and bridges.
Now, there is little traffic to disrupt, traditional targets of popular unrest - a parliament building, government office or bank headquarters - are mostly empty, and some activists are reluctant to venture out due to fears of catching the virus.
But protesters have learnt to adapt.
Swedish climate change activist Greta Thunberg, who set in motion climate strikes by school children worldwide, has shifted emphasis to social media, with her followers posting photos of themselves at home with banners and placards, and holding webinars and video discussions.
Serbians also found a way to make their protest heard without leaving home. For two nights last week, a cacophony of tin pans, drums, whistles and horns reverberated through much of the country as citizens, stuck at home under curfew, vented their anger at the government's tough containment measures.
In Athens, Greeks took the traditional approach on May Day, turning out in front of parliament, but they used red ground markers to ensure they obeyed social-distancing rules.
"The time has come to fight and to live," hospital union official Elias Sioras told hundreds of masked and gloved Greeks neatly spaced more than a metre apart.
"The battle is twofold, to stay healthy and to fight for a free public healthcare system."
Many of the protests bubbling away across Europe are focused on national lockdowns, either calling on governments to lift them or demanding more state support to endure them. Others are picking up on grievances that predated the pandemic.
In Poland, women took up their campaign against a renewed push by conservative activists to limit abortion rights, sidestepping a lockdown ban on public gatherings by posting slogans on social media, car windows and black umbrellas.
In Britain, environmentalists against a planned high-speed rail link, known as HS2, took advantage last month of a loophole in lockdown rules - you can still climb a tree.
"This tree is threatened by HS2 as are thousands up and down the country, but we can stop this," said Larch Maxey, one of several protesters who scaled a tree near an HS2 site outside London's Euston station, in a video posted on social media.