First:
If you already are in germany there´s another bunker you should visit:
Bunker "Valentin" - Bremen / Farge
A planned dockyard for the final assembly of type XXI sections. This is pure concreted megalomania...
Dont know if they do the tour in english too. And you´ve to hand out your passport for the time in there. This is still german army territory (material depot 2)
They will leave within the next time.
Hope this bunker will survive. Funding of security and maintenance is not secured now...
Second:
Technikmuseum Sinsheim and Speyer - a huge and well preserved collection of (not only) WWII tanks, planes and much more.
Fint it
Here - Speyer and
Here - Sinsheim