There were quite a few. But you're probably thinking of Guernica, which was bombed by the German airforce, in an attack which inspired a painting by Picasso.
Guernica
Germany supported Franco during the Spanish Civil War of 1936, and tested their weapons during that war.
Italy Germany
There were an estimate of 80 forts that were attacked during the Civil War.
Both sides in the Spanish Civil War received aid from outside Spain. France did not receive aid during or as a result of the Spanish Civil War.
Spain, during the so-called Spanish Civil War, which was a full-blast WAR,.
They remained neutral despite Germany and Italy offering official military support.
The Spanish Civil war provided opportunities for the equipment and weapons to be tested.
The Soviet Union ... plus assorted individual socialists. Britain
Germany and Italy took part in the Spanish Civil War, testing their soldiers and weapons.
The Spanish Civil War was a rehearsal for Germany to test out some of its weapons and leaders. The Germans sent the Condor Legion to fight in Spain.
It was a civil war. That means they fought themselves. In this particular case, the Army fought the government.It was an internal Spanish War with Portugal, Germany and Italy supporting Franco and the Soviet Union and the International Brigades supporting the legitimate government of Spain.