In this beautiful VIS image, taken by the NASA - Mars Odyssey Orbiter on June, 12th, 2004, and during its 11.060th orbit around the Red Planet, we can see a small part of the long (approx. 636 Km - such as about 394,956 miles) and extremely interesting Outflow Channel known as Mawrth Vallis, near to the point where it empties into the Martian Region of Chryse Planitia.
Mawrth Vallis has an elevation of approximately 2 Km (such as about 1,242 miles) below the "Datum" of Mars (---> such as "Zero Altitude", or, for Earth, the "Sea Level"); as we already wrote above, it is an ancient Outflow Channel, with light-colored Clay-rich Rocks (very well visible here). As a matter of fact, Mawrth Vallis is one of the oldest Valleys of Mars.
Just out of curiosity, Planetary Scientists believe that, some time (a LONG time) after its formation, it was, subsequently, almost completely covered by Layered Rocks, from beneath which it is now being slowly exhumed. Last, but not least, the Mawrth Vallis Region holds special interest because of the abundant presence of Phyllosilicate (---> clay) Minerals which, as you know, only form if and when (and for a long period of time!) Water is available
Latitude (centered): 25,6292° North
Longitude (centered): 341,2300° East
This image (which is an Original Mars Odyssey Orbiter falsely colored and Map Projected frame published on the NASA - Planetary Photojournal with the ID n. PIA 19785) has been additionally processed, magnified to aid the visibility of the details, extra-contrast enhanced and sharpened, Gamma corrected and then re-colorized in Absolute Natural Colors (such as the colors that a normal human eye would actually perceive if someone were onboard the NASA - Mars Odyssey Orbiter and then looked down, towards the Surface of Mars), by using an original technique created - and, in time, dramatically improved - by the Lunar Explorer Italia Team.