View of the north polar region of Mars from orbit. The ice-rich polar cap (quasi-circular white area at center) is about 1,000 km across. It is bisected by a large canyon, Chasma Boreale, on the right side. Dark, spiral-shaped bands are troughs. Chasma Boreale is about the length of the Grand Canyon in the U.S. and up to 2-km deep.
Credit: NASA/Caltech/JPL/E. DeJong/J. Craig/M. Stetson