Perhaps one day daylight "bent" by a sufficiently strong black hole and turned back toward the Earth can be collected and analyzed revealing pre-historic and possibly even ancient conditions of the world. Of course, this would be birds-eye, but who can fathom the ability of light to be analyzed by sensors developed several millennia hence. Man may one day obtain images of the Permian–Triassic extinction event, flocks of pterosaurs migrating, or something as detailed as Socrates being led off to prison for his execution.