Dreams, by Dumbledore

After Siruis Black entered the castle in search of Peter-Pettigrew-cum-Scabbers and Dumbledore had relegated the students to the Great Hall to sleep, Snape entered into conversation with him.Eventually, the following line passed Dumbledore's lips: "In dreams we enter a world that is entirely our own. Let them swim in the deepest oceans or glide over the highest cloud." I overlaid that quote on the ceiling of the Great Hall, which that night was emblazoned more with galaxies than mere stars. Click the image to see it better.