From 4.40 to 7.45 in the late afternoon of Monday 26 April 1937, the small Basque town of Guernica was destroyed by sustained bombing attacks by Adolf Hitler’s Condor Legion and Mussolini’s Aviazione Legionaria. The operation was supervised by Colonel Wolfram von Richthofen, the Condor Legion’s chief of staff, a brilliant and ruthless Prussian aristocrat with a doctorate in engineering.


A cousin of the First World War fighter ace ‘the Red Baron’ (Manfred von Richthofen), Wolfram had planned the entire operation as an experiment in terror – as he would later mastermind the Blitzkrieg in Poland and France. His choice of projectiles aimed to cause the greatest possible number of civilian victims. A combination of explosive bombs and incendiaries rained on the residential sector of the town, which was largely made of wood. And to prevent the fires being put out, the municipal water tanks and the fire-station were the first targets.

General Franco (centre) pictured in August 1937
General Franco (centre) pictured in August 1937. The general’s attempts to deny responsibility for the bombing of Guernica turned into a public-relations disaster for his forces. (Image by Getty Images)

Terrified civilians fleeing to the surrounding fields were herded back into Guernica by the machine-gun strafing of German fighter aircraft that circled the town in what Richthofen called “the ring of fire”.

Monday was market day in Guernica. Between the townspeople, refugees, peasants bringing goods to the market, and train loads of visitors from Bilbao coming to buy food, there were at least 10,000 people crammed into the town that day. They were attacked by 28 German and three Italian bombers together with 10 Heinkel He 51 and 12 Fiat CR32 biplane fighters and possibly six of the first ever Messerschmitt Bf109s. It was an operation on a scale that could hardly have been organised by the Germans behind the backs of the Spanish staff, with whom there was, in any case, constant liaison.

Diabolic forces

The horror unleashed that day was captured in the eyewitness account of the Basque priest Father Alberto Onaindía. “The explosion of the bombs, the fires which were beginning to break out and the harassment of the machine-gunning planes forced us to take cover under trees, under house entrances, dropping to the ground in the field when we saw a plane approaching. There was no anti-aircraft defence, no defence of any kind, we were encircled and corralled by diabolic forces in pursuit of defenceless inhabitants. Through the streets wandered the animals brought to market, donkeys, pigs, chickens. In the midst of that conflagration we saw people who fled screaming, praying, or gesticulating against the attackers… I had other bombing experiences later in England during the Second World War. But I never felt so unprotected and so much a defenceless victim as on that April 26th of 1937.”

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The exact number of victims of the bombing that day will never be known because of the immediate chaos and the fact that forces of General Francisco Franco – one of the leaders of the rebels whose military uprising had triggered the Spanish Civil War the previous summer – occupied the town three days later.

No effort was made to clear debris until after the end of the Civil War in 1939. All evidence of the bombing was removed, and no record was kept of bodies recovered.

Estimates as to how many people died in Guernica have varied widely. Pro-Franco accounts suggest that the number was below 200. But, based on the testimony of medical personnel in Guernica on the day and in nearby hospitals that received casualties, the Basque government estimated that 1,645 people were killed and a further 889 injured in the attack. (It’s thought that hundreds died asphyxiated in bomb shelters as fires sucked up the available oxygen.) The most recent research suggests that the truth lies near to, or even higher than, the Basque government’s estimate. Whatever the true death toll, as the first near-total destruction of an ‘open’ town in European history, Guernica was burned into the continent’s conscience as Franco’s great crime.

What happened at Guernica was consistent with threats made by General Emilio Mola, the man who masterminded the military coup that aimed to unseat Spain’s Republican government. “It is necessary to spread terror,” he declared on 19 July 1936, just a day after the coup began. “We have to create the impression of mastery, eliminating without scruples or hesitation all those who do not think as we do.” Rebel forces did precisely that in all of south-west Spain, the conservative areas of Old Castile, and Galicia in the north.

Franco’s principal objective was the Republican capital, Madrid, but it held out and, in mid-March 1937, his own troops and those of Italian leader Benito Mussolini were defeated at the battle of Guadalajara (40 miles north-east of the capital). It was now that Franco made a strategic volte-face.

Nationalist general Emilio Mola
Nationalist general Emilio Mola declared that it was “necessary” to spread terror. (Image by Getty Images)

With the Republic concentrating its best troops in the centre of Spain and neglecting other fronts, Franco accepted the case for victory by instalments elsewhere. Colonel Juan Vigón, chief of Mola’s general staff, argued for priority to be given to operations in the north to strengthen the rebel war effort by the seizure of the coal, iron and steel reserves and armaments factories of the Basque province of Vizcaya. The commander of the German Condor Legion, General Hugo Sperrle, agreed, promising that Basque resistance would crumble under concerted airborne attacks.

Rapid denials

By the end of March, Mola had gathered a large army backed by the air support of the German Condor Legion and the Italian Aviazione Legionaria (both countries backed the rebel side in the conflict), all under Richthofen’s command. Mola issued a threat that was both broadcast and printed in a leaflet dropped on the main towns: “If your submission is not immediate, I will raze Vizcaya to the ground, beginning with the industries of war. I have ample means to do so.” He then unleashed a massive four-day artillery and aircraft bombardment of eastern Vizcaya in which the small country town of Durango was destroyed. One hundred and twenty seven civilians were killed and a further 131 died shortly after of their wounds. Franco’s headquarters in Salamanca denied the bombing and attributed the damage to the Basques themselves.

Franco was delighted to have the crack Condor Legion as part of his forces. He allowed Sperrle and Richthofen a free hand to liaise directly with Mola and Vigón. This gave the Germans the decisive voice in the campaign. Sperrle wrote in 1939: “All suggestions made by the Condor Legion for the conduct of the war were accepted gratefully and followed.”

A French poster invokes Jesus Christ to condemn the barbarity of the bombing of Guernica
A French poster invokes Jesus Christ to condemn the barbarity of the bombing. (Image by Getty Images)

While the advance was being planned, Richthofen wrote in his diary on 24 March: “We are practically in charge of the entire business without any of the responsibility.” On 28 March he added: “I have established effective ground/air command.”

In expecting Vizcaya to fall in three weeks, Franco and Mola had underestimated the determination of the Basques. Steep, wooded hills, poor roads and heavy rain and fog had helped the retreating Gudaris (Basque soldiers) to delay the attacking forces. With Franco and Sperrle frustrated by the slowness of the advance, Richthofen used terror bombing to break the morale of the civilian population and to destroy communications where roads passed through towns. That was the purpose of the destruction of Durango and the intense bombing on 4 April of the Basque town of Otxandio.

Sperrle, Richthofen, Mola and Vigón now talked increasingly of reducing Bilbao to “debris and ash”. By 24 April, after merciless air bombardment and artillery pounding, the Basque forces were falling back in disarray. On 25 April, Vigón agreed to Richthofen’s plan to combine the tactical objective of blocking the retreat south of Guernica near Marquina with the broader strategic coup of a devastating blow against the Basques. That night, rebel radio at Salamanca broadcast the following warning to the Basque people: “Franco is about to deliver a mighty blow against which all resistance is useless. Basques! Surrender now and your lives will be spared.” A day later, Guernica would feel the full force of Mola’s threat.

Distraught officials

On 26 April 1937, four journalists covering the conflict – the Australian Noel Monks of the Daily Express, the Scotsman Christopher Holme of Reuters, the South African George Steer of The Times and the Belgian Mathieu Corman of the Parisian Ce Soir – spent 15 minutes in a bomb crater west of Guernica being strafed by the machine-guns of six Heinkel 51s. Later that night, they were having dinner when a distraught Basque official came in with news that Guernica was burning. They abandoned their table and drove to the town, which was still ablaze when they arrived at 11pm. They watched helplessly as weeping Gudaris frantically tried to dig out the bodies from the ruins. Steer interviewed survivors in the smoking ruins until the early hours of the 27th – “my authority for all that I have written”, as he later noted. He returned to Bilbao, spoke to more survivors and then drove the 15 miles back to Guernica to view the damage in daylight.

Steer found three silver tubes of German incendiary devices which accorded with a Richthofen diary entry about the “complete technical success” of his selection of the unusual bombload of explosive ‘splinter’ and incendiary bombs. His innovative thinking was that, while bomb craters in roads could be filled, massive destruction of buildings was a more effective obstacle to retreating troops.

Steer’s account of what he witnessed was published on 28 April in The Times and reproduced in the New York Times. Subdued and unsensational in tone, it provoked a world-wide storm of concern and was one of the most important reports filed by a journalist during the Spanish Civil War. More than any other commentator at the time, Steer managed to incorporate into his despatch a vivid sense of the scale of the atrocity.

“In the form of its execution and the scale of the destruction it wrought, no less than in the selection of its objective, the raid on Guernica is unparalleled in military history. Guernica was not a military objective. A factory producing war material lay outside the town and was untouched. So were two barracks some distance from the town. The town lay far behind the lines. The object of the bombardment was seemingly the demoralisation of the civil population and the destruction of the cradle of the Basque race.

“The whole town of 7,000 inhabitants, plus 3,000 refugees, was slowly and systematically pounded to pieces… In a street leading downhill from the Casa de Juntas I saw a place where 50 people, nearly all women and children, are said to have been trapped in an air raid refuge under a mass of burning wreckage. Many were killed in the fields, and altogether the deaths may run into hundreds.” (George Steer’s name was, incidentally, placed on the Gestapo’s Special Wanted List of 2,820 persons to be detained after a future German occupation of Britain.)

Wholesale arson

Steer’s perception that this was a new kind of warfare ensured that his despatch would have a deeply disturbing impact on both sides of the Atlantic. The New York Times editorial on the following day condemned “wholesale arson and mass murder, committed by rebel airplanes of German type”. It was reprinted in full on 29 April in the French communist daily L’Humanité, where it was read by Pablo Picasso. At the time, Picasso was working on a commission by the Spanish Republican government to provide a mural for the great Paris exhibition planned for summer 1937. Already affected by Louis Delaprée’s despatches about the bombing of Madrid, he began work on what would become his most famous painting.

Despite, or rather because of, the overwhelming verisimilitude of Steer’s report, the rebels immediately denied that Guernica had happened. The head of their foreign press bureau, Luis Bolín, claimed that Guernica had been dynamited by Basque saboteurs.

The Condor Legion sent in a team to remove bomb fins, unexploded bombs and other signs of the bombardment. Franco issued a statement that: “Units of our front line requested the air-force to bomb the crossroads, a request fulfilled by German and Italian aircraft, and because of poor visibility caused by smoke and clouds of dust, bombs hit the town. Therefore it is not possible to permit an investigation. The reds took advantage of the bombing to set fire to town.” What was most striking was the admission that the raid was requested by the Spaniards.

That the target could have been the crossroads, or the nearby stone Renteria bridge over the river Mundaca – as Franco also claimed – is contradicted by the weight of bombs dropped, and the preponderance of incendiaries, ineffective on stone.

Human catastrophe

The Basque army had been retreating along the roads towards Guernica, but it had not yet reached the town. Franco and Bolín clearly did not wonder why the Basques would dynamite the town and do precisely what Richthofen hoped to do – cut off the retreat by placing a massive human catastrophe in their path. Nor did they seem to ask themselves why dynamiters allegedly carrying out a scorched-earth policy left the small arms factory and the crucial bridge intact.

Franco’s claims were also contradicted by eyewitnesses, who testified that the conventional bombers used over Guernica flew low enough to have been able to drop bombs with some accuracy but flew too wide apart for concentration on a specific target. In fact, under the Renteria bridge was the safest place to be in Guernica during the bombing.

The only controversy still swirling around the atrocity is the question of who should shoulder the greatest blame – Franco’s high command or the Nazi Condor Legion? It is certainly the case that the head of the Luftwaffe, Hermann Göring, hoped to show Hitler that terror bombing was the best and the most National-Socialist way of winning a war. Convincing Hitler of the destructive capacity of the Luftwaffe would advance Göring’s ambition of taking control of Germany’s war industries. As such, it seems that he played a key role in the decision to bomb Guernica.

The German, Italian and Spanish high commands agreed that the best way to break the stubborn resistance of Bilbao was the annihilation of a Basque town. The date for the attack was dictated by the fact that the Monday market day was when most civilians would be present. It has been suggested that Göring had initially favoured an attack on 19 April, the day before Hitler’s 48th birthday. Because the necessary additional aircraft had not arrived in time, the operation was delayed by one week, as indeed were the celebrations in Berlin of the Führer’s birthday.

Franco had, of course, admitted his own involvement. On 18 September 1970, when he presided over the world championships of the Basque sport jai-alai in San Sebastian, Joseba Elosegui, a Basque nationalist, set fire to himself. Elosegui had been in command of the unit of Gudaris present in Guernica on 26 April 1937. By hurling himself in flames in front of the dictator, Elosegui hoped to make him understand what the Basque people had suffered in their flesh during the rebel campaign. Franco remained coldly impassive as the badly burned Elosegui was taken away. His disregard for the fate of the Basques was as harsh in 1970 as it had been in 1937.

Paul Preston is Príncipe de Asturias professor of contemporary Spanish history at the London School of Economics. His books include The Spanish Civil War: Reaction, Revolution and Revenge (William Collins, 2016)


This article was first published in the May 2017 issue of BBC History Magazine