With the focus on dramatic images of German riot police using tear gas and high-powered water cannons to disperse G20 protesters in Hamburg on Thursday, the message from those demonstrating in the streets was clear for those willing to listen: a better world is possible.

As world leaders arrived and with as many as 100,000 protesters expected, German officials have been steadily criticized for the intense security measures at the G20 Summit, which officially begins Friday.

Ahead of this week's mass demonstrations, the NoG20 International Coordination said in a statement: "The politics of neoliberalism and war is decided in the heart of our cities, closed off to citizens, protected by a militarized police force and backed up by the suspension of political rights. This shutting-down of democracy has one purpose only: to defend the indefensible. Our demonstrations speak for and of a different world."

In recent days, officials established a 15-square-mile no-protest zone around the airport and convention center, putting distance between world leaders and the thousands of people protesting the summit.

"It is very disturbing to know that some of the worst and most antidemocratic politicians will be coming to my city," George Letts, one of many Hamburg residents who have joined protesters who have traveled from across the globe for the demonstrations, told The Guardian. "A lot of people in the city want to show how democracy works as a sign to the Trumps, Erdoğans and Putins of the world. But the hard restrictions by the local politicians and police authorities make it difficult to demonstrate."

The BBC reports "clashes began when police charged a group of anti-capitalist demonstrators at the march attended by thousands carrying banners with slogans such as 'Welcome to hell' and 'Smash G20'. They fired water cannon and pepper spray at masked protesters, who hurled bottles, stones and flares at police."

Police use water cannons as they clash with activists protesting the G-20 summit in Hamburg, Germany. https://t.co/NATXlo9ARX pic.twitter.com/Na2lEvhtyL — ABC News (@ABC) July 6, 2017

Police told the Telegraph that violence ensued after protesters donning black face masks refused officers' requests to remove them. "G20: Welcome to Hell" is a slogan claimed by a group of anti-globalization activists—one of several groups that registered to demonstrate in Hamburg this week. Today's "Welcome to Hell" march was officially cancelled amid the clashes with law enforcement, but many remain in the streets. There have been reports of injuries among police forces and protesters, many of whom have attempted to flee demonstration areas following the violent encounters.

BREAKING: 1000s of protesters and police clashing outside G20 in Hamburg; protesters fleeing over wall. https://t.co/36dwuHKNcu — NBC Nightly News (@NBCNightlyNews) July 6, 2017

Despite today's clashes, more peaceful protests earlier this week highlighted demonstrators' urgent demands that G20 leaders reconsider their favored nationalist and neoliberal policies on war, immigration, environmental policy, and a slate of other issues.

On Wednesday, Hamburg saw a thousand "zombies" covered fully in grey clay, stumbling and crawling down the city's streets. These political zombies have popped up across the city in recent days, culminating in a march against "political apathy" and the "destructive impact of capitalism."

For those who look past the violent videos flashing across televisions screens around the world on Thursday, activists flooding Germany's streets offer complex and provocative challenges to how global superpowers enact policies and press their agendas.

"The world is in chaos. And Trump is a kind of symbol of that. But at the same time, there’s more energy than I’ve seen for a very long time behind the idea that we need to build something else, something very different."

—Nick Dearden, Global Justice Now

"For anyone with the ambition of constructing a true democratic politics beyond borders, the best ideas aren’t likely to come out of the official G20 Summit but to be found on the streets of Hamburg," Lorenzo Marsili and Giuseppe Caccia wrote for Policy Critique. "Today's crisis of global governance also offers the chance to move beyond a system that never truly worked in the first place."

But as Srecko Horvat wrote for Al-Jazeera this week, as much as public demonstrations are "necessary in order to show the massive dissatisfaction with the current global system…. even if there are 150,000 people in the streets, this massive mobilization won't produce any concrete change." In Horvat's view, the global left must continue to offer positive solutions while also creating "a new Non-Aligned Movement, which would work towards implementing these constructive policies."

Discussing shared ambitions to overall global politics, Nick Dearden, of Global Justice Now, said on Democracy Now! Thursday:

"We’re talking about how to build an alternative world. The background noise is the noise of activism. And everybody here is extremely thoughtful. We’re having many debates about the kind of world that we actually want to see, as opposed to the G20 world that’s been created, and really a very vibrant mood. Of course people are scared. I mean, people are scared about what’s happening in the world today. The world is in chaos. And Trump is a kind of symbol of that. But at the same time, there’s more energy than I’ve seen for a very long time behind the idea that we need to build something else, something very different."

Watch the full interview below: