A book could be written about the fascination Paris sewers hold, not only for twentieth-century tourists but for much nineteenth-century literature. Hugo, however, sums up neatly their persistent attraction for the inquiring mind: their technical ingenuity, their participation in the romance of "secret passageway," their grim summation of human existence.
Hugo skillfully weaves them into the epic pattern of his novel. They not only serve as counterpart to the passage in which he describes the "underworld mine" of criminal Paris, but provide him with a structural, picturesque, and psychological climax to a long sequence of similar scenes. Jean Valjean had fled alone in fear, carrying the beloved burden Cosette; now he flees with Marius, carrying hatred and despair on his back. He has experienced many scenes of darkness: darkness lit by a crucifix in the bishop's chamber, darkness lit by the moon with Cosette at the well, darkness lit by a flaring torch at the barricades; but now the darkness is total and absolute.
