Marathon Valley, seen through the robotic eyes of Opportunity has published a very high resolution (17.000x6000 pixels) image of Marathon Valley on Mars surface.

The image is a merge of multiple pancam exposures taken during the period April 16 through May 15, 2016 by Rover Opportunity on Mars:

The high point in the right half of the scene is “Knudsen Ridge,” which forms part of the southern edge of Marathon Valley. Portions of the northeastern and eastern rim of Endeavour crater appear on the distant horizon. Endeavour Crater is 14 miles (22 kilometers) in diameter.

A full resolution TIFF file is available, the link is PIA20749_full.tif.

Just a note from JPL website:

This file may be too large to view from a browser; it can be downloaded onto your desktop by right-clicking on the previous link and viewed with image viewing software.