The city itself boasts a technology level that’s at least a decade beyond the rest of the world, filled with cleaning robots, clones, and hi-tech computers and satellites. Academy City, being where the majority of the story takes place, boasts a population of over 2.3 million, with eighty-percent of those being students and involved in the Esper Development Program, a process that modifies someone's brain so that they are capable of using psychic powers. The divergence point stems from several decades in the past, when the greatest magician in the world, Aleister Crowley, decided to abandon magic in order to pursue science and founded Academy City. These two sides, Magic and Science, are carefully balanced to prevent the world from falling into turmoil, but several figures move to upset that balance for one reason or another, and it is often up to the protagonists to stop it. Through countless experiments, researchers are now capable of granting individuals superpowers through modifications to their minds, in a world where magic and religion hold great sway in the shadows. The setting of the To Aru series, that is both Toaru Majutsu no Index (A Certain Magical Index) and Toaru Kagaku no Railgun (A Certain Scientific Railgun), is a world where science has progressed to a profound degree in contemporary time.
