How are works of art that present scenes that match potential expectations processed in the brain, in contrast to such scenes that can never occur in real life because they would violate physical laws? Using functional magnetic resonance imaging, we investigated the processing of surrealistic and naturalistic images in visual artworks. Looking at naturalistic paintings leads to a significantly higher activation in the visual cortex and in the precuneus. Humans apparently own a sensitive mechanism even for artistic representations of the visual world to separate the impossible from what potentially matches physical reality. The observation reported here also suggests that sensory input corresponding to a realistic representation of the visual world elicits higher self-referential processing.