This is actually a video of Mars of one of the NASA's rover. I took the trouble to capture some screenshots of that video. Just take a look at how that sky looks. So gray. The carbon dioxide makes it look gray while the ground seems to look reddish because of sulphur. Impressive!
(Unfortunately, the option to upload videos is unavailable here, otherwise I would've uploaded it here) :
Breathtaking views. Of course, NASA has managed to have better recordings of the Martian soil and aspect of that planet's atmosphere. This time, they seem not to be computerized.