London Underground sign

LONDON, UK - APRIL 20: Underground sign at Westminster station in London on April 20, 2012. London Underground, the oldest metro system in the world, carries more than one billion passengers a year.

britaincapitalcitycolorcommutedestinationenglandiconicinformationLondonmetroredsignstationsubwaysymbolsymbolstourismtouristtraffictraintransporttransportationtraveltriptubeukundergroundwestminsterDSC1339