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ValveTime.co.uk | Valve News, Forums, Steam
First of all, if you haven't yet checked out Google Earth, do so.
With Google Earth, you can zoom-in on Sofia, Bulgaria - which is the city that is speculated to have most influenced the style of City 17.
If you go to 42° 41' 32.45" N by 23° 18' 37.96" (right above the Sofija marker) you can see a courtyard that looks a lot like the one outside the train station on Arrival.
. . . and if you zoom-in on the buildings across the courtyard, you can see a little Gordan Freeman running on top of the rooftops. . . just kidding.