1. The cracked and curving Martian rift valleys in the center are called Noctis Labyrinthus, or Night Labyrinth. Two dormant volcanoes are visible: Arsia Mons, top right, and Pavonis Mons, bottom right.
2. The largest canyon in the solar system, Valles Marineris, on Mars, is almost 2,500 miles long — nearly as long as the continental United States is wide. A ground fog hugs the canyon floor. Haze in the thin Martian atmosphere is visible on the horizon.