Decorative  sculptures on the roof  of the Reichstag with a  view of the glass dome			Dome and cone Following the design of Lord Foster, and in close co-operation with engineering specialists, the refurbished parliament building has been crowned with a roof structure that is as elegant as it is audacious. This structure, a steel and glass dome of roughly 23 meters height and a diameter of 40 meters, serves the natural illumination and ventilation of the debating chamber. For visitors, the upward spiralling walkways inside the dome are the main attraction, offering, as they do, a fine view out over the central area of Berlin, and into the heart of the building. 24 vertical steel ribs, which rest on a circular girder form the main framework of the dome, while 17 circular, horizontal steel rings give the dome its lateral stability. Between these rings, 17 rows of 24 mm thick glass panes, are arranged like the scales of a fish to form the dome's individual segments. Inside the glass dome two covered ramps arranged in the form of double-helix, allow visitors to climb up to the observation platform under the dome's apex.
	Cone with  diverting elements			Internally, the vertical dominant of the dome is the cone, a trumpet-shaped funnel of 360 separate mirrors, which directs daylight into the debating chamber some 10 meters below. To avoid direct sunlight being reflected down into the debating chamber, the mirrors facing the sun can be shielded by a computer-controlled shading device, which has a rotating steel frame and aluminium shutter elements, and can move with the sun according to the time of day and season of the year.
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				The BBB's projects Planning history The basic architectural concept from a city planning point of view A historic shell covering a hi-tech heart