The Metropolitan line is part of the London Underground. It is coloured in TfL's Corporate Magenta on the Tube map and in other branding. It was the first underground railway (or subway) in the world, opening on 10 January 1863. Today, part of that section are no longer served by the Metropolitan line, but by the Hammersmith & City, District and Circle lines. The main line runs from Aldgate in the City of London to Amersham, with branch lines to Uxbridge, Watford and Chesham. The line once went as far as Verney junction. After it was bought by the London Passenger Transport Board, the line was first cut back to Aylesbury, then to Amersham