London Underground ticketing destinations and most interchange stations are in zone 1, meaning that most journeys over similar distances will cost the same. A few stations in the north east of the network, on the Central line, outside Greater London (in the Epping Forest district) are in zones 4, 5 and 6. In the north west of the network, on the Metropolitan line, zones 7, 8 and 9 (formerly A - D) cover stations outside Greater London including Amersham and Chesham in the Chiltern district of Buckinghamshire. Unlike the lower numbered zones, these ancillary areas do not encircle the capital. Some stations are
M25 motorway M25 motorway The M25 or London Orbital Motorway is long encircling almost all of Greater London, England (with the exception of North Ockendon). An ambitious concept to build four concentric ring roads around London was first mooted in the 1960s. A few sections of the outer two rings were constructed in the early 1970s, but the plan was abandoned and the sections were later integrated to form a single ring which became the M25, aka London Ring Road, finally completed in 1986. It is one of the busiest of the British motorway network: the stretch between Junctions 14 and 15