It is actually the parliament building. A feature that makes it worth visiting here; The glass dome on top of it. Both very interesting and impressive structure, as well as offers city views. It's a good idea to take a look at it here as far as Brandenburg Tor. Reichstag's glass dome on top is a marvel of engineering, light striking the dome, which can reflect the parliamentary hall with a structure consisting of mirrors at different angles, using purify the rain water on generating power from solar panels . When you go up to the glass dome, do not forget to take it from the headphones that describe in detail the Berlin view in the direction you are looking at. One of the praiseworthy events in the history of building as an interesting statistic is that Hitler has never set foot on this building. If you are going to visit , make sure to book in advance.