Around 4.30pm on April 26, 1937, a joint squadron of 23 German and Italian planes appeared in the skies over the historic, and undefended, Basque town of Gernika. Over the next five hours they would drop a total of 22 tons of high explosives and incendiary devices that would burn for days, destroying 70 percent of the town, and killing and wounding 1,600 people - around a third of the population.
Gernika became a powerful symbol of the atrocity of war. Unknown to the people of the town, they had been slated by General Franco and his fascist allies to become guinea pigs in an experiment designed to determine just what it would take to bomb a city into oblivion. Franco knew that the large number of outsiders attending the weekly market had swelled its population that day.
Three-quarters of a century later, the only survivors of the attack were children at the time, and they have carried the horror of what happened with them all their lives.
"I still get very emotional when I think about that afternoon," says Andone Bidagueren, who was aged eight at the time. "I can't help it."
The Civil War had broken out nine months earlier, and cities such as Madrid, Barcelona and Valencia had already been bombed. Rumors had already begun to spread that Gernika's famous marketplace might be a target. Andone says that his mother rose early that day, heading for the town to sell milk. Around 4pm, she returned home. While he helped her with the empty milk churns, they heard the sirens ring out.
"We all ran off in different directions. Of my six brothers and sisters, three of us headed for the river. We thought that it would be the safest place," he says. The three hid in the water long after the bombing stopped, returning home only after dark. They heard their parents calling for them. "If the planes come back, we'll all die together at home," Andone's father told them.
The planes dropped 22 tons of high explosives and incendiary devices
Andone stayed in the town after the bombing, meeting her future husband, the son of a baker, the next day. But many other residents fled to France, among them Javier Alberdi, aged nine, and Luis Iriondo, aged 14. They returned a year later after Franco's forces had occupied Gernika, and along with around 200 or so other survivors, have remained there ever since.
Others never returned to Gernika, such as Francisco García San Román, aged seven, and his two brothers, who moved to another town. But they will be in Gernika for the commemorations of the bombing.
Aware of the risk of bombing, the municipal authorities had built air-raid shelters, and stationed lookouts atop the hills surrounding the town. They were to signal to other lookouts in church towers, who would ring the bells in the event of an attack. These steps undoubtedly saved many lives.
"When we heard the alarm bells, my cousin and I ran into the woods covering the hills," says Javier Alberdi. "We didn't stop until we reached the hermitage of Santa Lucía, about a kilometer-and-a-half from the town. When the bombing stopped, we went to one of my aunts. About three hours later my mother arrived," His wife Estibaliz Bidaguren, then aged six, says she remembers little: "All I can remember is being very angry with my father - I blamed him," she says. "I was a little girl and I didn't understand anything."
As would happen 50 years later in the Balkans, when Serb forces targeted Sarajevo's library, Franco and the Germans deliberately set out to obliterate Gernika's identity by dropping incendiary bombs, which would destroy the city's cultural and historical identity.
Gernika is the cultural capital of the Basque people, the seat of their centuries-old independence and democratic ideals. It had no strategic value as a military target. A few years later, a secret report to Berlin was uncovered in which Von Richthofen, the World War I fighter ace who commanded the Condor Squadron that led the attack, said: "...the concentrated attack on Gernika was the greatest success," making the intent of the mission clear: it had been ordered on Franco's behalf to break the spirited Basque resistance to his Nationalist forces. Gernika had served as the testing ground for a new Nazi military tactic: carpet-bombing a civilian population to demoralize the enemy. This would be put to terrifyingly effective use two years later, when Hitler invaded Poland.
Franco knew that the weekly market had swelled Gernika's population that day
As part of the commemorations, a group of historians has set about locating and interviewing the survivors of the bombing. In 2010, the Gernika Gogoratuz association brought out a book that recorded the testimonies of some 22 survivors. Since then, eight have died.
Luis Iriondo was alone when the bombers struck. "I found a shelter in one of the four bunkers that had been built in the town square. I can't remember how many of us there were. It was dark and I could hardly breathe. We ended up lying down so as to get more air," he says.
This year, Andone Bidaguren will go to the local cemetery and lay flowers at the memorial built in 1995 to remember the victims of the bombing. "I tell my grandchildren that this is something we should never forget."
On April 24, 1999, 61 years after the attack, the German parliament formally apologized to the citizens of Gernika for the role the Condor Legion played in bombing the town. The German government also agreed to change the names of some German military barracks named after members of the Condor Legion. By contrast, no formal apology to the town has ever been offered by the Spanish state on behalf of the Franco regime that ordered the attack.
The events of those three long hours on April 26, 1937 are not in doubt: German planes, flown by German pilots, and placed at the service of Franco by Adolf Hitler, destroyed Gernika. The question that remains controversial, 75 years later, is the motive. Why did the Condor Legion destroy this little Basque town? Historians of different ideological persuasions offer varied explanations.
The fact that a propaganda war about the bombing broke out the very day after it took place has muddled the events since then. Franco's propaganda machine tried to first deny the obvious fact that Gernika had been destroyed, and later even went so far as to claim that it had been blown up with dynamite - by the Basques themselves! There were others on that side, however, who made no attempt to deny what had happened. "Well of course it was bombed," one Franco official famously stated. "We bombed it, and bombed it, and bombed it - and well, why not?"
The controversy revolves around whether or not the devastation of the city was intentional or whether it was an unwanted consequence of an operation that sought the destruction of military targets alone, and whether the civilian casualties are what would now be described as collateral damage.
That is the line of thought favored by rightwing historians of the past, present and no doubt of the future. They have traditionally sought to play down the effect of the bombing and the number of planes and victims, and generally attribute the responsibility of the action to the Condor Legion - i.e. laying the blame at the door of the Germans, in an attempt to exonerate the Francoist high command and Franco himself.
In line with the argument that the attack was simply part of the war and that its intensity was not as great as some claim, as maintained by the Spanish historian Jesús Salas Larrazábal, who specializes in Civil War aviation, the Germans and the Italians attacked Gernika given its strategic and military value, as it was a significant transport hub. The bombers, the argument goes, were trying to destroy the bridge on the River Oca to avoid an enemy retreat toward the defensive positions in Bilbao, the main roads and the train station. It was the poor visibility caused by the clouds of smoke generated from the first wave of attacks that caused the planes to drop their bombs in the wrong place - i.e. on the town.
The famous German flying ace Adolf Galland, who took part in the Civil War, albeit not in Gernika, said that the bombing was a shameful error caused by the lack of skill of the crews and the primitive sights of the planes. The German military historian Klaus A. Maier concluded that the destruction was due to an unfortunate coincidence of unfavorable conditions.
But this argument, that the destruction of Gernika was down to the bad aim of the bombers, has been widely questioned. Historians such as Paul Preston argue that the attack must be framed within the context of the practice runs for mass bombings that the German air force was carrying out in Spain, and that were later replayed in the Blitzkrieg that devastated many cities during World War II. According to Preston in his book The Spanish Civil War: Reaction, Revolution and Revenge, the head of the Condor Legion, Wolfram von Richthofen (the cousin of the Red Baron), was a demanding and methodical professional, who was firmly committed to the use of terror.
Preston and other historians suggest that the massive use in Gernika of incendiary bombs - utterly useless as a weapon to destroy a stone bridge - prove that the plan was not a precision attack. To further back up this argument, historians point out that the more precise Stuka bombers were not used.
The US historian Herbert Southworth - cited by Preston as the world authority on Gernika - argued that the bombing was carried out on the request of the Francoist high command, with the objective of destroying the morale of the Basques.
Another prestigious historian who supports this thesis is Antony Beevor. In his book, The Spanish Civil War, the academic concludes that even if there were military targets, the aim was to carry out an experiment to verify the effects of terror from the air.
Gernika passed into the annals of history as the first European city destroyed by aviation. Many more would follow.