 320 standard routes through central London, or "runs", are defined in the "Guide to Learning the Knowledge of London", which is produced by the Public Carriage Office.In all, some 25,000 streets within a six-mile radius of Charing Cross are covered, along with the major arterial routes through the rest of London.A taxicab-driver must learn these routes, as well as the "points of interest" along and within of each end of those routes including streets, squares, clubs, hospitals, hotels, theatres, embassies, government and public buildings, railway stations, police stations, courts, diplomatic buildings, important places of worship, cemeteries, crematoria, parks and open spaces, sports and leisure centres, places of learning, restaurants and historic buildings.