I have seen almost any and all places in Germany (mostly during business trips, which I extended for private fun)

Here is my list, I have seen all but Rotenburg. Classification 1 to 6; 1 = you have to see, 6 = never go there.
Location: S=South, E=East, M=Middle, N=North, W=West. I added also places near the border.

Big towns:
Berlin 1,E
Munich 1,S
Hamburg 1,N

Smaller towns (50,000 to 900,000 inh.):
Luebeck 1,N
Schwerin/Wismar 3,N
Bremen 2,N
Worpswede 3,N
Lueneburg 3,N
Bamberg 2,S
Regensburg 3,S
Dresden 1,M/E
Heidelberg 3,M
Strasbourg, France 2,S/M
Salzburg, Austria 1,S
Nuernberg 3,S
Leipzig 3,M/E
Wiesbaden 3,M
Baden Baden 3,S
Potsdam 3,E
Weimar 3,M/E
Erfurt 3,M/E
Wartburg in Eisenach 3,M/E
Rotenburg odT 3 M/S
Wuerzburg 3,M
Cologne 3,M/W
Trier 3,W
Colmar, France 2,S/M
Ruedesheim 5,M
Villages near Ruedesheim 2,M

Interesting venues:
Rhine Valley 1,M/W
Mosel Valley 1,M/W
D'Alsac/Elsass, France 1,M/S
Black Forest 2,S
Spreewald 3,E
Lueneburger Heide 3,N
Starnberger See/Tegernsee 2,S

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