For decades "autonomen” - anarchists and far-left demonstrators - have held an annual "Revolutionary May 1st protest" in Berlin's Kreuzberg.
Past years have seen overturned police cars, Molotov cocktails flying through the air and hundreds of arrests and injuries.
This year promised to be one of the worst, as the extreme-right National Democratic Party (NPD) announced it would march through Neukölln, a multi-ethnic and alternative neighbourhood in Berlin, raising the spectre of street battles between ideological enemies.
But after hundreds of anti-fascist demonstrators blocked a similar march through Kreuzberg last Saturday, the NPD decided to cancel the Labour Day event.
IN PICTURES: Neo-Nazi march blocked in Berlin
Far-right and neo-Nazi marches will, however, take place in other cities throughout the country.
The Berlin NPD march has reportedly been moved to Rostock, Mecklenburg-Western Pomerania, where anti-fascist groups are already gearing up for a possible confrontation.
The blog nazisstoppen.eu reported that three counter-demonstrations and a bicycle protest would be held in the city.
"We can't let Nazis march undisturbed within sight of the Sunflower house," said the website, referring to the site of xenophobic race riots in 1992. "Let's be loud and creative and spoil their day!"
Police also confirmed to The Local that an NPD march would be held in Duisburg, in the industrial Ruhr area, where anti-fascist groups are also active.
Even with neo-Nazis absent from the streets of Berlin, left-wing activists are still planning a range of activities that risk bringing them into conflict with law enforcement.
An unregistered protest is set for 5pm on Mariannenplatz in Kreuzberg, with the slogan "Fed up - demonstration for a good life, with access to housing, education and culture for everyone!"
Organizers explain that they have not registered the protest with police because they refuse to "ask permission of those... who throw us out of our houses with brutal violence when we can't afford the rent, who control people daily, and even detain and deport them, just because they don't like the colour of their skin".
They even sent a direct warning to the police stating: "We don't need police for our demonstration - on the contrary. So stay far away from us... lay in the sun and think a little bit about your rotten and evil job as a state employed thug. Or use your free day to write your notice and burn your uniform and weapons."
By 6pm the unregistered demonstration should join the main body of the Revolutionary May 1st protest on Lausitzer Platz in Kreuzberg.
Organized by numerous anti-fascist and socialist groups, the protest traces its history back to the 1987 Kreuzberg riots, which saw police cars overturned, clouds of tear gas and a supermarket set on fire.
The following year, 10,000 people marched through Kreuzberg in the first Revolutionary May 1st protest, which also ended in rioting.
Radical left-wing protesters use the event as a pretext to go to war with police, throwing bottles and stones, breaking windows and starting fires.
Police respond with water cannons, tear gas and brute force. One of the worst years was 2001, when 270 police officers were injured, leading to 289 arrests.
Massive police presence
The past few years have seen some decline in the level of violence, particularly due to a family-friendly festival that has been organized in the same area since 2003, drawing in enough peaceful bystanders to dampen the ardour of protesters.
"My-fest" is still decidedly left-wing, with punk music performances and comedy shows taking place blocks away from an "anarchist academy", but police are still not taking any chances.
Riot police from all over Germany will be streaming into the capital to keep the area under control.
Between 10,000 and 15,000 protesters are expected to attend this year, according to media reports drawing on organizers and police sources. Police are responding with a force of 7,000 riot officers, who will be heavily armoured with 22 kilos of protective gear.
‘Hamburg sees red’
Hamburg is also bracing for possible clashes on Thursday, as left-wing activists organize an event entitled "Hamburg sees red" in the alternative Schanzenviertel district.
May 1st last year saw about 1,600 riot officers on the streets of Hamburg.
Peaceful May Day celebrations will also be taking place across the country, with the Federation of German Trade Unions holding its main demonstration in Bremen.
Union leaders will be placing attention on fighting against exceptions to minimum wage laws, improving pensions and opposing austerity measures across the continent.
But with all eyes turned toward the spectacles of violence expected elsewhere, such demands might be drowned out by the crash of breaking windows and the acrid smell of tear gas.
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