In April 1937, Guernica was the first city to be deliberately targeted for aerial bombing. Over 1,600 civilians perished in the world's first sustained aerial bombardment of a civilian population. News of the massacre reached Paris where Picasso was living. Newspapers were filled with photographs of the smoldering ruins of Guernica, and after having seen those photos Picasso began working on sketches for a mural that was to become one of his most famous works.