Stockholm's metro boasts 100 stations that can take visitors to various points of interest downtown as well as many areas in the outskirts, between the hours of 5 a.m. to 1 a.m. during the week ...

From there I headed to Berlin and finally Stockholm, with a couple of short stops in-between. In all, I spent 14 days spread between five cities, spending over 100 hours photographing metro stations.