This is one of my favorite images from Curiosity so far: a shot by one of its navigation cameras showing the distant rim of Gale crater. It's several kilometers away, and looks for all the world - all the worlds - like a mountain range. I see very similar-looking hills when I ride my bike north of my home in Boulder, Colorado! But not even our air is as thin and dry as that on Mars.
In the foreground is of course the rover itself, and the crater floor reaches into the distance, covered in loose pebbles. Image credit: NASA/JPL-Caltech