Reichstag, which is now home of the German Parliament. Due to some terror alarm, you have to book the visit online and go through heavy security checks, so I would advise to get there around 30 min before the start of the visit.
The building in itself is amazing, our visit was focused on art & architecture, we could see lots of artworks exposed there, as well as the graffitis from the Soviet soldiers when they took over the Reichstag in 1945. There is another interesting artwork, looks like archives, each "box" labeled with the name of those who sat at the Parliament, no one has been forgotten, and a black box represents the 12 years of nazi.
We finished the tour on the roof, with the famous glass dome, which was added after the 3rd Reich period, so that the people could look into the parliament room and that the deputies never forget who they are working for: the people. Plus, the view from there is amazing!
Here are some pictures.
==Greetings from Berlin==