On the grounds of Dresden’s trade fair site, visitors emerge from the cellar of a former abattoir. Most of it was recently turned into a cloakroom but it partly retains its original look, of shiny white tiles and a stained concrete floor. A plaque identifies it as Schlachthof 5 [Slaughterhouse 5].

This is where Kurt Vonnegut, along with 159 fellow US soldiers, was held as a prisoner of war. It’s also where he experienced the 1945 firebombing of the city, protected from death by the thick walls of the meat vault in which he was held, the place that would inspire his 1969 cult anti-war satire, Slaughterhouse-Five.

“It’s probably one of the few places in the city where you’re reminded of the bombing, but only really if you know where to look,” says 39-year-old Danilo Hommel who takes tourists on daily tours of the city which, through the eyes of the writer, focus on the allied air raid that reduced the baroque city to something resembling a moonscape.

Hommel points also to a nearby “rubble mountain” in the western district of Ostragehege. The recreational spot was formed from the vast amount of smithereens – from crumbled buildings to crushed human bones – that resulted when 2,400 tons of explosive bombs and nearly 1,500 tons of incendiary devices were dropped from RAF and US air force planes in four raids on the city between 13 and 15 February 1945, in an attempt to bring the war to an end.

“Most Dresdeners are hardly aware that it consists of war rubble, and few would dare contemplate that it contains human remains,” Hommel says.

On Friday the city will mark the 70th anniversary of the bombings, which killed 25,000 civilians, many of whom if not blown up, were asphyxiated or burnt to death.

Citizens will come together to commemorate the bombing at an array of ceremonies, bell-ringings, readings and plays, with a speech by the German president, and a human chain where candles will be lit in silent tribute to the victims of war.

But Dresden is approaching this major anniversary with considerable trepidation after the most tumultuous months in its recent history, following the rise of the anti-immigrant movement Pegida, which at its height has attracted 25,000 protesters to its Monday evening demonstrations.

Attacks on foreigners have risen 130% since the autumn, according to Danilo Starosta, an expert on the far-right with the Dresden group Kulturbüro Sachsen, who blames Pegida for creating a “poisonous atmosphere” in the city.

Commemorations are taking place against the backdrop of a deeply divided city. “There’s a crack running through the city, with one half for diversity, openness and tolerance, while the other half is fearful or hostile, against foreigners, even against people not from [the local region] Saxony,” says Dresden-based political scientist Hans Vörlander.

That divide is perhaps most palpable outside the Semperoper concert hall on theatre square, which has been the scene of several Pegida demonstrations,

Christian Thielemann, chief conductor of the Staatskapelle Dresden, who was keen to stress that the opera house is no “ivory tower” but says: “Our artistic and technical crews have felt uneasy coming to work on Mondays, scared that they’ll be hit by stones or bottles, having to elbow their way through ... the noise and braying of the indignant crowds to get to the stage.”

The “Pegida divide” is to be felt just as acutely among the opera house’s employees as elsewhere in the city.

Pegida has attracted a considerable gathering of far-right demonstrators, and a leader, Lutz Bachmann, who has posed as Hitler and called immigrants “cattle” and “scum”. But largely its core of supporters are middle-class, middle-aged and well-educated, earning above the average wage. The group has been vague about its aims and unwilling to communicate, but those participants willing to talk express a wish to rid Germany of “criminal asylum seekers” and their fear of the “Islamisation” of the western world. But above all the feeling that they have is of having been hard done by.

Vörlander puts the movement’s relative success down to “decades, even centuries” of a culture of “self-reference and narcissism, which coincides with a feeling of being an innocent victim of circumstance”. It is, he adds, one of the consequences of living in such baroque splendour that Dresdeners “define themselves through the past, not the future”. Historians say that, terrible though the destruction of Dresden was, there was nothing remarkable about it.

“Hamburg, Cologne and Pforzheim suffered more,” says Thomas Widera, a historian at the Hannah Arendt Institute at Dresden’s technical university.

Allied carpet bombing had been going on under the command of, Arthur “Bomber” Harris since 1942, with the lesson learned from the Nazi bombing of Coventry in 1940 that bombing a whole city was more effective than focusing on single targets.

But Dresden soon became the German equivalent of Hiroshima, a status it has never really lost.

“While cities like Rotterdam and Coventry are seen to have ‘moved on’, Dresden is stuck in its past,” says Widera.

First it served as an effective propaganda tool for the Nazis, then for the communists, and in the last 20 years has been used by neo-Nazis who use the anniversary to demonstrate against what they refer to as the “bombing Holocaust”, equating the event it to Auschwitz and viewing Germans as the victims, the allies as the perpetrators.

Widera says many Dresdeners choose to ignore that the bombing did not take place in isolation.

“Don’t forget that Auschwitz was liberated just about two weeks before the bombing of Dresden,” he says. “And the pictures that emerged from Auschwitz were far more shocking than those of a destroyed Dresden.”

Unlike Berlin, where second world war bullet holes are still visible in many buildings in the city centre and Nazi crime scenes are signposted and preserved, Dresden has done its best to remove the stains. Many of its baroque buildings have been restored at huge effort and cost, most famously the Frauenkirche, which until the mid-90s was still a huge pile of charred stones but in the past few years has been painstakingly reconstructed. Its facade is a strange mix of charred-black (4,000 of the original stones) and sand-coloured stones, which locals say with pride will, thanks to the elements, one day be indistinguishable from each other, so that no one need talk about the day it was destroyed or why.

Dresdeners have long been divided between those who want to rebuild the city as it was – sometimes dubbed “baroque fascists” – and those who favour the modern (“modernist barbarians”).

Those who are critical of Dresdeners’ lack of self-scrutiny – their failure to recognise what a Nazi stronghold the city was or the high degree of antisemitism that existed – argue that it is dangerous and distasteful to rebuild the city without comment on the past.

“The Frauenkirche could have been a memorial. Instead it’s been shaped by this desire to get rid of traces of the war. As a historian, I think it’s wrong that it’s so pristine,” says Widera.

Dresdeners are responding in different ways. Outside the Semperoper, huge banners bear the slogan “Eyes Open, Hearts Open, Doors Open”, while at the Academy of Arts, windows have been painted with the messages “Dresden for All” and “Refugees Welcome”.

Mercedes Reichstein, a feminist activist, has gone further still in her response to the revisionism and the rise in intolerance, with an invitation to British bombers to repeat the actions of 13 February 1945. She has painted her naked chest with “Bomber Harris Do it Again” in a viral photograph.

Meanwhile, Hommel is struggling with Dresden’s authorities to keep the remaining piece of the Vonnegut cellar as it is. “So much of Dresden’s historic charm – by that I mean the genuine stuff – is obsolete,” he says. “Even if some things, like the cellar, are not so attractive, it would be nice to keep them as they were to act as a reminder of what happened, because that sense of connection is the only way you can have an emotional response to it and the only chance we have of stopping history from repeating itself.”