In this Viking 1 image, the canyons are filled with mist from frost sublimated by the early-morning sun. (South is toward the top.) Courtesy NASA/JPL-Caltech.

Noctis Labyrinthus, "the labyrinth of the night", is a region of Mars between the Valles Marineris and the Tharsis upland. The region is notable for its maze-like system of deep, steep-walled valleys.