One of six Flak towers from the World War II in Vienna. This one is the tallest of towers. Its walls are 2.50 meters, the roof 3.60 meters, thick. In 1946, about 2000 grenades, which had been stored underneath the roof, exploded in the tower. Since then, the tower is considered to be in danger of collapsing. See the steel ropes wrapped around it? Their purpose is to give additional stability to the tower.
The photo is an HDR shot from three photos at intervals of 1.7 stops. I created the HDR in Photomatix [Homepage Link]. Then I reduced noise with Nik Define 2.0 [Homepage link] and finally sharpened it with Aperture [Mac App Store link].