Prospective London black cab drivers must complete a rigorous training process known as "The Knowledge," which involves memorizing the layout of the city within a six-mile radius of Charing Cross. This includes mastering approximately 320 standard routes (often called "runs") found in the official "Blue Book." Beyond these routes, they must also memorize 25,000 streets and roughly 20,000 landmarks or "points of interest"—ranging from museums and hospitals to obscure pubs and statues. The goal is to ensure that a licensed driver can navigate the shortest path between any two points in the city entirely from memory, without the aid of a GPS. This mental feat typically takes three to four years of daily study and practice on a scooter, followed by a series of grueling oral examinations with a Transport for London (TfL) examiner.