German cities with important military industries and Berlin as the center of the Third Reich, were protected by massive Flak-towers. However, Hitler also ordered to built several of them in the capital of Austria, Vienna. Contrary to most German cities and especially Berlin, the Flaktürme of Vienna survived to this day as architectural landmarks rising above the city skyline.
The pictures were made by Henk Adriaanse in 2009.

The cityscape of Vienna