The Mars Global Surveyor was in operation around the Red Planet for over nine years. From 1997 to 2006 it snapped away with its Mars Orbiter Camera, taking more than 240,000 images. One of these pictures from the MOC is circulating the web right now; but no one is giving the supplemental info on what it is or linked to where it's from! So I'm chiming in.
The picture was taken in May 2003, but its impact has not lessened with time. It shows Earth and Jupiter in one shot as seen from Mars! The whole image can be found here, but it's huge (basically a long strip) so I've extracted the two planets here:
Whoa. You can clearly see the Earth and Moon, and even the continent of South America! On Jupiter, the banding of the clouds of obvious, as are three of the Galilean moons.
But I think you really need to click through and see the whole image (as well as the accompanying explanation on the MOC site). In this case, context is important. It's critical! It's images like this that remind us that we live on a planet, a world like any other and yet unique in that it's our home. I get people asking me if space exploration is worth it, and then I see images like this, and I know the answer is yes. We need this perspective. It's said that the Apollo 8 shot of the Earth rising over the Moon launched the modern environmental movement, because it showed all of us eggs sitting in our one, lone basket. We should be reminded of this idea as often as possible, and images like this one from the MOC need to be spread far and wide.