If you have ever lived in Vienna, you will probably have taken the Viennese underground (U-Bahn) at one time or another. The current U-Bahn system consist of 5 lines - U1, U2, U3, U4 and U6 - and each line has a distinct feel to it. There is a very different atmosphere on the U4, for example, than on the U6. The journalists of NZZ.at wrote 5 articles about the 5 metro lines, analysing the phenomena of U-Bahn life and the contrasting worlds of each underground route.
Read more on NZZ.at here