Geograph - photograph every grid square

Holloway Road is a station on the London Underground. It is on the Piccadilly line between Caledonian Road and Arsenal stations, and in Travelcard Zone 2. The station opened in 1906.
The station was constructed by the Great Northern, Piccadilly and Brompton Railway.
Grade II listed. Link
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".

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

Mark Wallinger, one of the UK’s leading contemporary artists, has created a major new artwork for London Underground to celebrate its 150th anniversary. The result, commissioned by Art on the Underground, is a multi-part work on a huge scale that will be installed in every one of the Tube’s 270 stations.