Viking Orbiter images still provide some of the best color views we have of Mars. This view shows Gale crater and adjacent regions of Mars, including a large stretch of the "dichotomy boundary," the scarp that separates Mars' southern highlands from its northern lowlands.
Original images f681a06, 10 and 12. Calibrated, map projected in ISIS3. Merged to RGB in Photoshop. The version above has had its color tweaked slightly to appear more "realistic." Here is a PNG version without that tweaking.