Be careful regarding Guernica. While it was hugely impactful in popular memory it was not as unprecedented as it might seem. For instance, bomber attacks on London in WWI had similar casualty counts (depending on whose estimates you choose). One could track the success of the Schnellbomber concept and chart why Germany came to rely so heavily on that (flawed) idea.

You mentioned armored tactics, and one could trace this via reactions to the Battle of Guadalajara. The French and British saw the failings of Italian armor and concluded that their doctrines were correct--armored breakthroughs were not the wave of the future. The Germans took the opposite conclusion--that Italian tankettes didn't have the punching power to accomplish their goal but almost did anyway despite being left hung out to dry by Franco.

I'm not so sure one could successfully argue that German remobilization was hidden by its involvement in Spain. Check out Cry Havoc by Maiolo for insight regarding French and German estimates of German capabilities.

Spanish economic concessions to gain German support could be relatively easily tracked, and there has been a good deal of work on the Blue Division of Spaniards that served on the Eastern Front.

I would suggest reading the European sections of Cry Havoc as it has a good deal to say about the attitudes of the later combatants of WWII. I would also council caution regarding conclusions about the Spanish Civil War. It can be tempting to give the conflict too much credit for later historical decisions.

If you wanted to study the impact on the French, one could investigate the relative positions of Action Française and other right wing movements compared to the various left wing countermoves. Since most of these movements had newspapers tracking their ideological response to the Spanish Civil War could be fruitful.

Hahah, even now that I am old and also the chairman of the presidium of the League of Yugoslav Communists, I remember that time so well.

Back in the day when we fought out fight for national liberation aganst the fascist invader and occupant, traversing the mountains of Montenegro, the valleys of Serbia, the hills of Croatia, one thing that saved our Partisan behinds was the training so many of us had received during the Spanish Civil War. Organizing the people's resistance was a difficult task, trust me, druze, on that (not made easier by those Stalinist bastards in Moscow telling us to hold back until June) but our best assesst really were the fighters who had fought against the fascist thread in Spain.

In 1935/36 I was acutally send by the Comintern (which I co-founded btw.) to Paris in order to recruit as many comrades as possible into the cause of fighting alongside our comrades from all over Europe and the world against the Franco-fascist thread. Abou 1.600 comrades heard the call of our Spanish brethren and joined the International Brigades, mostly fighting in the Dimitrov and Đuro Đaković Brigades, taking part in such battles like the Battle of Ebro in 1938. Sometimes I wish I could have been there.

After the loss brought on by the international support of the fascists and the treachery of the revisionists, the remaining 800 Yugoslav comrades were interned in France but many also made it home. When the fascists attacked Yugoslavia in 1941, some of them would be our greatest assets. Of the 4 armies of our glorious Partisan Liberation Army, 3 would be lead by some of our finest veterans from Spain: Peko Dapčević, Kosta Nađ and Petar Drapšin. Koča Popović.

Brave comrade Dapčević went to Spain in 1937 where he became a political commissar in the Dimitrov Battailon and fought in the Battle of Ebro. Later he would lead the Partisan armies in Montenegro and Bosnia and play the pivotal role in my greatest strategic design, the battle of the Neretva, where he freed Dreznica and Jablanica and was pivotal in occupying the fascist occupier so that our troops could escape over the Neretva. In 1944 he and his . Partisan Army would liberate Belgrad together with Comrade Zhukov's forces.

Fine comrade Nađ joined the troops in Spain after illegally crossing the border because he had been arrested in Austria and Switzerland on his journey. A sergant in charge of one of our brigades, he was our last commander pulling out of Spain üprotecting the retreating troops herocially in 1939. During the war of liberation, he was on my staff and fought our biggest battle during the whole war, the battle of Bihac.

Unbeatable comrade Drapšin fought in the fields of Andalusia from 1935 on where he earned many honors not just of the Yugoslav but also of the Spanish people. During the war of national liberation he became my deputy commander in Croatia and in 1945 when we formed the Yugoslav People's Army he was its first commander.

The names of our heroes of Spain are numerous and include great comrades from Franc Rozman to Ivan Gošnjak. Without theri experience in Spain, the struggle of the Yugoslav peoples against the fascist invaders and occupiers would have been much much harder.

I've done all I can to ensure that this post is within the guidelines of /r/AskHistorians, I apologise if it isn't.

The Spanish Civil War was fundamental to the development of the Luftwaffe, but the bombing of Guernica was a small part of that (despite the wider attention it received). It came at an opportune moment for the nascent Luftwaffe, rapidly expanding at the outbreak of the war in 1936 and starting to put a second generation of aircraft into service, combat experience teaching key lessons for the Second World War including:

• Air Transport. The first contribution of German aircraft was participating in the airlift of Franco's Nationalist troops from Africa to mainland Spain. The Junkers Ju 52 transport was pressed into service as a bomber when the Luftwaffe was first formed, and fared poorly in this role in Spain, but the war demonstrated the importance of air transport. As dedicated bombers such as the Heinkel He 111 came into service the Ju 52s were converted back to transport aircraft, the backbone of Luftwaffe airlift capability in the Second World War.

• Fighter Tactics. Under Werner Mölders, German fighter squadrons adopted a system based on a pair of aircraft (Rotte) consisting of a leader covered by a wingman. Two pairs made a Schwarm. This loose formation proved more effective than the tight three aircraft 'V' formation used by e.g. the RAF at the start of the Second World War, in which most of the attention of the wingmen was on keeping formation rather than scanning for the enemy, and was eventually adopted by most air forces.

• Close Air Support. The Spanish Civil War was an object lesson in the practical difficulties of directly supporting ground units from the air; initially, for example, aircraft could communicate with each other, or their home base, but not directly with troops on the ground. With improved communication and liaison teams working with army units, the Condor Legion effectively supported the Army in both defensive and offensive operations, vital experience for Luftwaffe support of army operations in the Second World War. The RAF all but ignored army co-operation in the inter-war years, and suffered painful lessons on the road to forming an efficient tactical air force.

• Ineffectiveness of City Bombing. Though the bombing of Guernica may have fuelled wider public fears of the apocalyptic nature of air bombardment (fears that, as /u/Domini_canes says, were stoked in First World War and peaked in the inter-war years, e.g. Baldwin's "the bomber will always get through" speech), the civilian population was probably not the primary target (see e.g. [Dr Brett Holman's blog] (http://airminded.org/2007/05/16/guernica-iii/)). The Condor Legion bombed Madrid in 1936, but failed to break civilian morale there; the Italian Aviazione Legionaria heavily bombed Barcelona in 1938, but again morale remained strong. Strategic attacks against industrial and transportation targets, by contrast, were effective.

Main source: The Luftwaffe and Lessons Learned in the Spanish Civil War, James S. Corum, from Air Power History: Turning Points from Kitty Hawk to Kosovo (ed. Cox & Gray).

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