To discover Germany by bicycle reveals the country in a whole new perspective and there are many regions we wouldn't recommend any other means of transport!
For example, cycling along the Danube or the Rhine River. Visit the Black Forest hills with its cute little villages or the Eastern Alps and Neuschwanstein castle. Cycle through the Ore Mountains discovering its crafts, the remains of DDR communist Germany or cycle along the northern or eastern sea with its cool and moderate summer climate.
Although maybe not quite as famous for cyclists as France, Italy or Spain, Germany compensates this lack of notoriety with its cycle friendly cities with a good network of cycleways, amazing cultural heritage and the famous German efficiency.
Some people still have the bad image of this country due to the time before and during WW2, but today Germany is a modern nation with a very colorful & multicultural landscape. However, for people who want to travel back in time, there are numerous places where contemporary history can be witnessed, history that is not just kept alive, but even well preserved.
From the cycle tourists' point of view the most positive is that much of these historical sights are in the countryside and therefore easy to reach by bike. If you do find yourself in a city, cyclists will appreciate the good arrangements for bicycles and respectful motorists.
All standards in Germany, in particular medical and hygiene are first class. Things are usually well organized and functional which makes it a place easy to travel.