The Panopticon is a type of prison building designed by the philosopher Jeremy Bentham. The concept of the design is to allow an observer to observe (-opticon) all (pan-) prisoners without the prisoners being able to tell if they are being observed or not.
The architectural figure "incorporates a tower central to an annular building that is divided into cells, each cell extending the entire thickness of the building to allow inner and outer windows. The occupants of the cells . . . are thus backlit, isolated from one another by walls, and subject to scrutiny both collectively and individually by an observer in the tower who remains unseen. Toward this end, Bentham envisioned not only venetian blinds on the tower observation ports but also mazelike connections among tower rooms to avoid glints of light or noise that might betray the presence of an observer."
Bentham derived the idea from the plan of a factory designed for easy supervision, and his design was intended to be cheaper than that of the prisons of his time, as it required less staff. As the watchmen cannot be seen, they need not be on duty at all times, effectively leaving the watching to the watched.
While the design had limited (if any) effect on the prisons of Bentham's time, it has been seen as an important development. For instance, the design was seen by Michel Foucault (in "Discipline and Punish") as an example of a new technology of observation which transcended to the army, the school and the factory. Variants of the panopticon can also be seen in the modern society as part of the surveillance society.
 Barton, Ben F., and Marthalee S. Barton. "Modes of Power in Technical and Professional Visuals." Journal of Business and Technical Communication 7.1, 1993. 138-62.