An oubliette was a form of dungeon which was accessible only from a hatch in a high ceiling. To exit an oubliette was impossible under any circumstances, without outside help. The word comes from the French oublier, "to forget," as it was used for prisoners whom it was desired to forget about. One example of a particularly claustrophic oubliette is in the dungeon of Warwick Castle, in central England. The castle is in Warwickshire County, the town of Warwick, and overlooks the River Avon. The access hatch consists of an iron grille secured by a hasp and (now) padlock.