A visit here is essential. You make an appointment via e-mail: http://www.bundestag.de. There are different visiting hours throughout the day (08:00 to 22:00). I saw it at night and although it was beautiful to see the city lights, I think it is advisable to visit in daylight. Not only is there the possibility to see where German politicians meet but it is impressive to see the architectural project created by Sir Norman Foster. Its showpiece is a spherical glass dome that lets you see the whole city from the top. There is a spiral walkway that runs along the entire dome. They say that Foster wanted to make it out of glass to show the transparency of the German government.
If you're in Berlin, it is best to book a morning or afternoon for a walk in the Charlottenburg Palace. It is very different from the modern Berlin we are used to .. When the city was largely destroyed in World War II, it was an old summer house, with well preserved gardens, ideal for a picnic, exercise, walking for a couple of hours or admiring its beauty. There is no charge for access to the gardens, but you must pay to go inside the palace.
This picture was taken in the park of Charlottenburg Palace-Castle, Berlin which has an impressive garden with squirrels and a lake full of ducks and swans, it's a beautiful space to relax and take some good photographs of animals.