Guernica in the context of Museo Nacional Centro de Arte Reina Sofía

On 26 April 1937, the Basque town of Guernica (Gernika in Basque) was aerially bombed during the Spanish Civil War. It was carried out at the behest of Francisco Franco's rebel Nationalist faction by its allies, the Nazi German Luftwaffe's Condor Legion and the Fascist Italian Aviazione Legionaria, under the code name Operation Rügen. The town was being used as a communications centre by Republican forces just behind the front line, and the raid was intended to destroy bridges and roads. The operation opened the way to Franco's capture of Bilbao and his victory in northern Spain.

The attack gained controversy because it involved the bombing of civilians by a military air force. Seen as a war crime by some historians and argued as a legitimate attack by others, it was one of the first aerial bombings to capture global attention. Under the international laws regarding aerial warfare in 1937, Guernica was a legitimate military target. The number of victims is still disputed; the Basque government reported 1,654 people killed at the time, while local historians identified 126 victims (later revised by the authors of the study to 153). A British source used by the USAF Air War College claims 400 civilians died. Soviet archives claim 800 deaths on 1 May 1937, but this number may not include victims who later died of their injuries in hospitals or whose bodies were discovered buried in the rubble.

The Battle of Belchite refers to a series of military operations that took place between 24 August and 7 September 1937, in and around the town of Belchite (almost 4,000 inhabitants in 1936, decreasing to around 2,600 during the battle, from the repression and displacement of the first year), in Aragon during the Spanish Civil War, as part of a much bigger offensive to take Zaragoza, that continued until the beginning of November 1937.

Since the Offensive of Zaragoza failed, the Republicans started calling it Battle of Belchite for propaganda reasons instead, so that it would look like a victory, the journalists that came to report the victory, including Ernest Hemingway, contributed to this change of names. The Nationalists continued the confusion, since they exploited the "Numantine" defense of the town for propaganda too, to counteract the bad image of the bombing of Guernica.