(This takes 4½ minutes to read.)
Wanting to prevent an encirclement of communist and socialist governments as well as needing a testing ground for the newly militarized Luftwaffe, Hitler committed the Condor Legion of bombers to aid General Franco’s Nationalist forces in Spain.
The Condor Legion served as a laboratory for Luftwaffe command, and almost every lesson learned during the Spanish Civil War informed [Luftwaffe] strategy during the coming conflicts. The culmination of the educational experience for Condor Legion commanders was the bombing of the city of Guernica. Immortalized in human consciousness by Pablo Picasso’s namesake painting, Guernica represented the beginning of prominence for terror bombing in German doctrine.
On a relatively quiet afternoon in April, countryside traders made their way into the small town in order to participate in the weekly market day. At the time, few to no soldiers resided in Guernica and as a result the war had not yet touched it. Roberts suggests that the Condor Legion’s commander selected the town for this exact reason. He would be able to measure the destruction caused by an attack accurately.⁵
Some traders were turned away by town guardsmen because the church bell rang out, signaling an incoming air raid. Unfortunately, not everyone was so lucky. After an initial attack run from a single Heinkel-111, one of which is shown in Figure 1, second and third waves of bombers caught first responders trying to help the wounded as well as destroying buildings that had not yet been damaged.⁶
A British Pathé video captured images of steaming piles of rubble in place of some buildings. Teams of men dug out survivors and moved corpses wrapped in blankets. Whole truckloads of families evacuated the city. Guernica’s civilians would not escape Fascist wrath, however, as their flight took them further into the “Iron Ring” around the Republican stronghold of Bilbao. Soon German, Italian, and Spanish Nationalist forces attacked Bilbao even more brutally.⁷
After the Heinkel medium bombers exhausted their reserves of incendiary bombs, the civilians of Guernica once again believed [that] they were safe. They ventured out to assist the dead and dying. Once again, the [Fascists] had set a trap. Dust kicked up around the Spaniards as [Fascist] fighters strafed the streets with machine guns and pilots dropped grenades on clusters of defenseless people on the ground. After the attack, in the words of one reporter who was an eyewitness to the bombing, “large parts of Guernica aren’t a shell but an ash heap.”⁸
The concept of attacking a civilian population with such unflinching ferocity was so unheard of that people around the world had difficulty accepting that such an event had even occurred. Only days after the attack, The Sun in Baltimore published a story by G.L. Steer confirming reports of a [Luftwaffe] attack on the Spanish city.⁹
Steer felt the need to strike down claims that no such attack had ever occurred. He did so by recounting his harrowing experience on the day of the attack. He spoke of being machine-gunned and detailed the planes with unmistakably [Fascist] markings attacking the city. The day after the attack, Steer went into the town to find evidence. He discovered fragments of bombs “exactly of the same metal as bombs lately used by Gen. Emilo Mola’s German planes on the front line,” which also bore the [Fascist] crest of the golden eagle.¹⁰
Some, including the mayor of Guernica, refused to believe that a planned attack with this level of viciousness could have happened. Steer provided compelling evidence that the Luftwaffe was more than capable of executing such a diabolical plan. Finally, the [Fascist] experiment in bombing for terror ended with more twisted success than Ludendorff or even the Legion’s commander, the infamous [Fascist] field marshal Hugo Sperrle, had likely hoped for.
Relatively few casualties plagued Guernica by comparison to World War Two standards, but the breach of wartime etiquette signaled much more sinister acts of war to come. The bombing of Guernica became, in Stephens’ words, “the symbolic act that defined the greater atrocity—a calculated attack on a town or city crowded with civilians,”¹¹ and this atrocity returned with the [Fascist invasion of Poland].
Military historian James Corum identified the connecting thread between the Spanish Civil War and [the rest of] World War Two, saying “the Condor Legion’s experience in breaking the Basque fortifications at Bilbao in June 1937 foreshadowed the use of massed German aircraft to destroy the Polish fortifications at Modlin in September 1939.”¹² Similarly, the same tactics used at Guernica returned time and again in civilian centers of Poland, France, the Low Countries, the Soviet Union, and Great Britain.
Lessons learned from the Condor Legion were applied in [Luftwaffe] operations training throughout the Second World War. An inferno rained from the skies over Warsaw, Rotterdam, the Champagne city of Mareuil, Paris, London, Moscow, and London once again between the years of 1939 and 1945.¹³
[…]
In May 1940, the New York Times published a column claiming that Hermann Göring, the supreme commander of the Luftwaffe, threatened retaliatory strikes against Great Britain, specifically using the word terror in its inflammatory language.²¹
Promising “mighty blows” against the British body and flexing the perceived muscle of the [Luftwaffe], Göring was laying blame for his intentional targeting of civilian populations squarely on British military operations against Germany.²²
While this was framed as a retaliation for British operations and the Blitz—an all-out aerial assault aimed primarily against civilians which lasted almost a full year—is often cited as the beginning of [the Third Reich’s] aggression towards civilian populations, that explanation is far from the truth.
It is important to remember that [Fascist] fire rained on Warsaw and other Polish cities months before the publication of this article, not to mention Guernica years before. While Göring threatened only Great Britain, the Luftwaffe went on to target Dutch and Belgian cities as well as French border towns like Mareuil with terror strikes only five months later, using the same methods that were tested at Guernica. The first sorties of the Blitz didn’t fly until early July of 1940, long after the Reichsmarschall made his threat.
[…]
From 1936 until the end of the Second World War, Göring was in charge of air force doctrine. It is highly unlikely that der totale Krieg’s doctrine was developed and tested in Spain, then implemented on an industrial scale in Poland and Western Europe, without Göring’s knowledge and support.
It is possible that he simply didn’t want to anger Hitler by committing Luftwaffe resources to other pursuits, but far more plausible that Göring himself saw merit in the terrorizing aspects of bombing noncombatant population centers. This is corroborated by Göring’s place as the very first to be named as a defendant at the Nuremberg Military Tribunal for Major War Criminals.³⁵
(Emphasis added.)