[{SlideShowNav}] !!! Y-shaped office buildings, Vienna [{Image src='450au.jpg' height='800' alt='Y-shaped office buildings, Vienna' class='image_left' width='600'}] [{SET customtitle='Y-shaped office buildings, Vienna'}] \\ A birds-eye view of two of the six Y-shaped office buildings, as well as the central cylindrical conference center, that make up part the United Nations Office complex in Vienna. In the distance is the 252 m (827 ft)Donauturn (Danube Tower) the tallest structure in Austria. In addition to its use as a communication tower, it also houses two revolving retaurants and has an observation deck.