It has been 80 years, but Polish pensioner Zofia Burchacinska has no trouble recalling the day her city, sometimes called the "Polish Guernica", became the first target of World War II.
"It was dawn and still grey out. I was woken up by a strange sound, a strong roar I'd never heard before," the now 91-year-old said of the heavy bombing of Wielun on September 1, 1939.
"Suddenly, the ceiling cracked and all the glass shattered. That's because our windows looked out on the street where the first bombs fell, on a hospital further down," she told AFP.
The attack on the small central city of Wielun has been called a kind of Polish-Jewish Guernica.
But the raid, at the beginning of World War II, is less well-known than the Nazi bombing of the Basque town two year earlier, during the Spanish Civil War -- captured in Picasso's masterpiece.
The exact number of Wielun's victims has never been established, but estimates range from several hundred to more than 1,000 killed. At the time, the city had a population of 16,000.
"Wielun, where children, women and the elderly died, is a symbol of total warfare," said Jan Ksiazek, a historian and director of a local museum.
Total warfare is the style of warfare that includes waging war not just on military, but on civilian targets.
The shrill sound Burchacinska heard as an 11-year-old was that of the sirens the Germans had attached to the landing gear of their dive bombers to scare the target populations.
The order to bomb Wielun was given by General Wolfram Freiherr von Richthofen, who also led the German unit that razed Guernica in 1937.
The similarities are striking: both cases involved bombing civilians of a defenceless city to spread panic.
"My mother and I fled across the marketplace, which was already full of rubble. Part of the square was on fire, the flames were fierce," Burchacinska said.
"I didn't return to Wielun until after the so-called liberation, with the arrival of the Bolshevik army," she added.
"I didn't recognise the city. My father had to lead me by the hand to school. There was no more marketplace, there were no more streets."
Only around 20 witnesses of the bombing still live in Wielun. Tadeusz Sierandt, eight years old at the time of the attack, also remembers the horror.
"People were running in all directions, they were fleeing, some without clothes. I saw dead bodies, the wounded.... Smoke, noise, explosions. Everything was burning," he told AFP.
Wielun was gradually rebuilt after the war. Today it is a bustling, beautiful city of 25,000 people with well-maintained streets and parks. It is proud of its identity as a former royal city founded in the 13th century.
"The only place where you can see blast marks is on the ruins of the parish church downtown, which shows you the extent of the destruction," deputy mayor Joanna Skotnicka-Fiuk told AFP. Everything else was rebuilt.
Wielun maintains ties to Germany by staying in touch with its partner cities. This year the relations will reach an unprecedented level with a joint visit from German President Frank-Walter Steinmeier and his Polish counterpart Andrzej Duda on the 80th anniversary.
Some have asked why the German army targeted a city without any military significance. The answer may lie in Wielun's ethnic makeup.
"The Germans were likely aware that Wielun was a bicultural city. The Polish population dominated, followed by the Jewish population," historian Tadeusz Olejnik told AFP.
In 1939, one-third of the city's residents were Jewish, he said, adding that "there was no German minority here, unlike in other cities in central Poland."
"When the bombs fell on the sleeping city, razing it, residents fled the inferno in droves, blocking roads and complicating the Polish army's movement," the Wielun-based academic said.
The Jews who survived were first enclosed in the Wielun ghetto, then as part of Adolf Hitler's so-called "Final Solution" they were sent either to the Lodz ghetto or the Chelmno nad Nerem death camp, where they were killed in gas vans.
