The picture on the right is an image of the Valles Marineris, the great canyon of Mars. It is like a giant version of the Grand Canyon. The image shows the entire canyon system, which is over 3,000 km long, stretching over about one-third of the planet. The canyon averages 8 km deep and might have formed from a combination of plate tectonics and erosion. Several craters are also visible around the canyon.