I'm sure as good as everyone in the world knows Berlin, the current and former capital of Germany. I'd hope as good as everyone knows that between that "current" and "former", there was an other capital of Germany, but I'm not sure about that. So, here's a photographic introduction to the town that was the capital of Germany (or at least the part of it that was not under communist dictatorship) from 1949 to 1999: Bonn.
The city has been designated with the, for Germany, unique title of federal city, is still the second official residence of the Bundeskanzler (president) and the Bundesrat (the upper house of parliament) - the first of course being Berlin - and the first official residence of six federal ministries and approximately 20 federal authorities.
It is however also the place where you'll find a number of more or less interesting musea (depending on your particular interests), a number of historical buildings and this enormous park, the Freizeitpark Rheinaue. Enjoy your walk !