Guernica WAS controversial when it was made (intentionally), but for political reasons, not artistic ones. The subject of Guernica was the slaughter of civilians by the Fascist government of Spain, which was allied with the Nazis. read more
Picasso's huge mural depicting the 1937 massacre of a Basque village, this painting is controversial for a number of reasons. As a decry against fascism, it's become known as "a picture of all bombed cities." Its home has been the largest point of contention because Picasso did not want it displayed in Spain until justice had been restored there. read more