I recently set myself the challenge to visit and photograph every station in Zone 1 of the London Underground. I only visit London occasionally but always have a camera with me and so inevitably take a few photos while I'm there. After talking photos in the Underground the first 3 or 4 times I realised I'd started a pattern which kind of self-perpetuated itself until I found myself having to make various detours and strange routes just to get to stations I hadn't been to yet.
It took quite a few months, but here is the end result...every station in Zone 1, all 63 of them...