Surrealism was an art of fantasy, dream, and the unconscious, delving into the recesses of the human psyche to discover mysterious, bizarre, and often disturbing images. René Magritte, however, was a Surrealist painter more fascinated by puzzles and paradoxes than by the nature of the unconscious. The Promenades of Euclid presents the age-old problem of illusion versus reality. In this witty picture within a picture, the canvas in front of the window seems to exactly replicate the section of city it blocks from view. But does it? Could the twin forms of tower and street exist only in the artist's imagination? Or do we view the actual city through a transparent canvas?