Mare Imbrium, from Galileo

Caption NASA originale:"Checking out the Galileo spacecraft's cameras during its December 1992 fly-by of Earth's Moon, controllers took this dramatically illuminated picture through a violet filter. The view looks down on the Moon's North Polar Region with the Sun shining from the left at a low angle and the direction toward the Moon's North Pole toward the lower right.
Across the image upper left stretches the smooth volcanic plain of the Mare Imbrium. Pythagoras crater, 65 miles wide, is near the center of the image -- mostly in shadow, its central peak just catches the sunlight (...)".