What happens if you try to combine 214 different subway networks -- including 791 routes and 11,924 stations -- into a single map? This beautiful tangle of colour and lines is what.
Created by New York-based ArtCodeData and Open Access, the map -- called, aptly, The World Metro Map -- includes subway systems from Istanbul to Seoul, New York to Moscow, Mexico to Taipei. There's been a lot of thought put into the thing, not least in careful colour selection and arrangement of the lines, to make sure it makes at least some sense.
It's obviously not particularly useful, of course, but the overall effect is rather beautiful. If you like it, you can support the project on Kickstarter and snag yourself a large print of the map.
Image by Open Access