Well, almost. This is a strange one. As far as I can tell, the photographer took the blues and crushed them so they are almost black, resulting in this abrupt transition from the white haze to the now really gloomy sky. Unusual - and not realistic at all - but striking.
So I went with it, and pushed the contrast and sharpness even more.
Not nature, but what can I do, I like New York. This one almost looks like an impressionist painting, with the beads of light shining from the shadows and reflected in the rain. Great atmosphere.
I just cleaned up the image a little, removed some noise, and crushed the blacks.
Well, this one definitelly is otherworldly. Apollo 17, the final moon landing. Sad that we haven't gone back.
The starting image was pretty low-res, but I think the blown-up version is just about acceptable. I found what I think was the original high-res panorama (linked above) on the NASA site, at least judging by Gene Cernan's position by the rover, but I didn't feel like cleaning-up the flare over the lander, because that's a lot of work. However, the rest of that panorama doesn't align perfectly with the one I used, so I guess they are slightly different composits. I took a bit of artistic license and added-in the Earth above the scene. The size should be about right, the position is not. Judging by the other photos from the same mission and the lighting, it should actually be to above and behind the camera. And since the moon is tidally locked to the Earth, that's where the Earth stays.
Other than that, I slightly increased the contrast and darkened the image. I allowed the lander to become more of a silhouette, so that the eye is drawn toward the rover and Gene.
This is really an otherworldly-looking canyon, and the lighting in the photo is great. I referamed it - I quite like the more abstract look without the sky that focuses more on the meandering shapes of the canyon walls.
Post-processing-wise, I upped the blacks, nothing more.