Martian Terrain

This high-altitude photograph shows a variety of the features on Mars,
including enormous volcanoes (left) on the highland, called Tharsis Bulge;
impact craters (upper right); and vast, windswept plains. The
enormous Valles Marineris canyon system crosses horizontally
just below the center of the image. Inset: Details of the Valles
Marineris, which is about 100 km (60 mi) wide. The canyon
floor has two major levels. The northern (upper) canyon floor
is 8 km (5 mi) beneath the surrounding plateau, whereas the
southern canyon floor is only 5 km (3 mi) below the plateau