While in Berlin, make some time to visit the Funkturm Berlin radio tower for some excellent high altitude view of Berlin.  With an observation deck 125m high, the views of the city are absolutely breathtaking.  From the deck, one can see the sprawling city blocks, beautiful forestry, and the Olimpiastadion.  After taking in the city, one can descend to the Funkturm Restaurant for a great meal while observing the city from 52m high.  This s a must-visit for anyone looking to snap great aerial photos of Berlin.  The tower is located on the Messe Berlin Exhibition grounds, a location for many exhibitions including the IFA worldwide trade show.
The tower opens on Mondays from 10 AM to 8 PM, and from Tuesdays to Saturdays from 10 AM to 11 PM.
Note that the restaurant is open Wednesday to Sundays from 11:30 AM to 11 PM.  It also opens on Tuesdays at 6 PM and is closed on Mondays.