Geograph - photograph every grid square

Bank and Monument are interlinked London Underground and Docklands Light Railway stations that form a public transport complex spanning the length of King William Street in the City of London. Bank station, named after the Bank of England, opened in 1900 at Bank junction and is served by the Central, Northern and Waterloo and City lines, and the Docklands Light Railway. Monument station, named after the Monument to the Great Fire of London, opened in 1884 and is served by the District and Circle lines. The stations have been linked as an interchange since 1933. The station complex is the one of the busiest on the London Underground network and is in fare zone 1.
Wikipedia: Link

The London Underground system is also known as the "Tube". It is the oldest underground system in the world, the first section dating from 1863. The present system has over 250 miles of track and 272 stations. There are 11 lines covering Greater London, Essex, Buckinghamshire & Hertfordshire. Nearly half the system is above ground.
Wikipedia: Link
Transport for London: Link

A few years ago I read a book by Mark Mason "Walking the lines" in which he walked the route of the London Underground lines, overground. I will repeat this visiting all 272 stations (some more than once). My route tries to follow the line of the railway as closely as possible, using footpaths and roads, deviations are made to make the walk more "interesting".