During the 1940s, many artists were influenced by World War II and used surrealism in their paintings to process the turmoil and tragedy of war. Some key surrealist artists of this time included Salvador Dali, who left Europe for the US in 1940 and had highly successful exhibitions. Pablo Picasso's work from this decade depicted darker subjects influenced by death and war. Norman Rockwell also created politically charged paintings in the 1940s in response to Roosevelt's speeches, with themes of freedom, to promote war bonds.