But What Color Is It?

I've been looking at the photos returned by the Mars Rover. They're really amazing. So far the neatest thing about these pictures isn't that the soil is largely red (duh), or that it deforms in a mysterious way when something heavy moves across it (the so-called Magic Carpet), or that we can see the images in 3D or as animations. For me, the neatest things about the photos is:

Mars has a sky!
K-