Memphis Facula in Galileo Regio on Ganymede ?
"Voyager 2 image of the Galileo Regio area on Ganymede taken from 126,000 km. The large bright circle at lower right is the 344 km diameter Memphis Facula. Above and right of it is Nidaba crater, 188 km across. Running vertically through the left center of the image is Lakhmu Fossa, a linear rift which runs over 2800 km. This is one of the images of "Ganymede City," mentioned in Arthur C. Clarke's "3001". The image is about 950 km across and north is up. (Voyager 2, FDS 20637.02)"