Juan Barjola was an Extremaduran painter born in 1919 who spent much of his career working in a figurative style that absorbed Spanish surrealism and expressionism into images of violence, sexuality, and dark Iberian mythology. His series based on Goya's "Third of May" is probably his most discussed work — paintings that treat the massacre of civilians in war as a recurring subject across centuries rather than a single historical event. The museum in Cimadevilla dedicated to his work holds the main collection: oils, drawings, and prints from throughout his career.
The museum is in a restored building in the old fishermen's quarter, small enough to see in an hour and specific enough that it doesn't wear out its welcome. Barjola is not a household name outside Spain, but his work is substantial and the collection here makes a good case for him. Visitors who come to Cimadevilla for the Chillida sculpture and the Roman baths often discover the Barjola museum by walking past it and being pulled in by whatever is in the window. That is probably the ideal way to encounter it — by accident, without too much expectation.