Map of Zone 1 Underground stations with streets shown
London is split into six approximately concentric zones. The boundary of Zone 1 corresponds roughly with the Underground's Circle line covering the West End, the Holborn district, Kensington, Paddington and the City of London. Old Street, Angel, Pimlico, Tower Gateway, Aldgate East, Euston, Vauxhall, Elephant & Castle, Borough, London Bridge, Earl's Court, Marylebone, Edgware Road, Lambeth North and Waterloo are in zone 1 but not in or on the Circle line. Every London Underground line has stations in zone 1. Underground stations within this zone are typically close together; for instance Covent Garden and Leicester Square are only 0.3 kilometres (0.2 mi) apart, the smallest distance between any two stations in the network. The zone originates from two central London zones that were created on 4 October 1981 named City and West End, in which flat fares applied, replaced in 1983 by Zone 1.