Christopher's journey from Swindon to London is approximately two hours by train. Once Christopher got to London he had to complete the tricky task of navigating the London Underground, also known as the "Tube." This rail system is divided into nine different zones. To properly use the map, you need to figure out which zone and station you are in and then find what train will take you to the zone and station you are trying to get to. I'd like to remind you that Christopher is fifteen and has never really been out on his own, so the fact that he was determined enough to complete this journey is incredible.