Simplify the following text for a Grade 8 native English-speaking person.
Original: Guernica is a painting by Pablo Picasso , in response to the bombing of Guernica , Basque Country , by German and Italian warplanes at the behest of the Spanish Nationalist forces , on 26 April 1937 , during the Spanish Civil War .
Simplified: It is a very large painting ( a mural ) which shows the bombing of the Spanish town of Guernica in 1937 during the Spanish Civil War .