Extending eastward from Tharsis is an immense canyon systemùValles Marineris. The largest surface feature on the planet, Valles Marinaris stretches over 3,000 miles and reaches widths up to 450 miles. Radiating outward are arrays of tension faults (graben). Valles Marineris ends in an huge region of chaotic terrain between Chryse Planitia and Margaritifer Sinus.
