(GMT)04 DEC 2016 J90TH:
The parliament building called the Reichstag is impressive. It was heavily damaged during World War II but fully renovated.
Foster was responsible for remodeling the building in 1996, and it incorporates a large glass dome you can go and from which have good views of the institutional area of Berlin. The main dome has been replaced by a futuristic piece of architecture. You really have to get inside the Dome where you can walk in circles to reach its top. There is a small opening where you watch the clouds pass by and the views on the city are an extra benefit.
Riechstag is close to the Brandenburg Gate, near the large park in central Berlin. Admission is free!