The ancient city of Trier deserves its high marks as one of the premier tourist destinations in Germany. Full of things to see and do, the city offer a complete package for visitors. Don't forget the beautiful region outside the city to explore.
Mainz is an often overlooked destination due to the destruction the city faced in WWII, but that should not be a reason to skip Mainz, as there is enough left to make it worth your time.
The city of Mannheim was once the illustrious capital of the Upper-Rhine, though virtually nothing survives. Nevertheless, since you might find yourself here by accident let me give you a quick tour of what's left.
Heidelberg's offers a small but highly concentrated dose of old-town architecture and old-world charm in Southern Germany. Its worth a visit, even with its reputation for tourists.
You will either spend two hours or two days here, depending on how interested you are in the history of the city and its cultural life. Let's take a look at what there is to do in the Imperial City of Aachen.