Valles Marineris: The Grand Canyon of Mars
This mosaic of Mars is a compilation of images captured by the Viking Orbiter 1.
The center of the scene shows the entire Valles Marineris canyon system, more than 2,000 miles (3,000 kilometers) long, 370 miles (600 kilometers) wide and 5 miles (8 kilometers) deep, extending from Noctis Labyrinthus, the arcuate system of graben to the west, to the chaotic terrain to the east.
The mosaic is composed of 102 Viking Orbiter images of Mars. Many huge ancient river channels begin from the chaotic terrain from north-central canyons and run north.
The three Tharsis volcanoes (dark red spots), each about 25 kilometers high, are visible to the west. South of Valles Marineris is very ancient terrain covered by many impact craters.
Infographic (with United States for Scale)