^ Thanks Stork100
just saw it, sorry for being late..
Berlin and "no water" were valuable hints, but i never saw the surface structure of the AVUS 'Nordkurve' so close. Really thought of an aerial photograph at first.
btw the abbreviation means "Automobil-Verkehrs- und Übungsstraße" (~Automobile traffic and test road), and some original portion is still part of today's Berlin city motorway. Too bad not this angled part though, would be fun to drive ..
