Ganges Chasma is part of the Valles Marineris canyon system that stretches nearly 5,000 kilometers (3,000 miles) across the western equatorial region of Mars. In the center of Ganges Chasma there is a huge stack of bright layered rock piled nearly as high as the outside rims of the canyon. A smaller outcropping of these layered rocks is visible in the lower right. The floor of Ganges Chasma is a thick, relatively flat sheet of dark windblown sand. The jumbled troughs and depressions that run from the north side of Ganges Chasma toward the upper right corner of the image were caused by a cavern forming under the surface followed by a partial collapse. Ganges Chasma is about 3 to 5 kilometers (2 to 3 miles) deep and this image covers an area 350 km (217 miles) wide. The image was taken by Mars Global Surveyor.   (39/53)