The Reichstag was originally completed in 1894 where the Neo-Renaissance palace served as the home of the German Empire's Imperial Diet until it burned in 1933.
It was not used again until after the reunification of Germany, at which point it underwent a ten-year reconstruction and finally became the home of the German Parliament in 1999.
A highlight of this magnificent reconstruction is the replacement dome, the Kuppel, made of glass and offering superb views of the surrounding city, especially at night from the Rooftop Restaurant.
Note that entry to the Dome and Terrace is ticketed, and due to demand, it's recommended that tickets be requested in advance (registration is available on the day, but expect a two- or three-hour wait).