New Photo of Mercury taken by NASA's Messenger probe. It was taken a few days ago. It's a photo of the previously unseen side.
It's visually not the most amazing planet, but still: it's a look at part of a world we've never seen. Those four or five dark-rimmed craters in the upper right seem to have thrown up a layer of grey dust around them. It's as if they covered up a large area on impact. We don't see that anywhere else on the surface.