Are there former concentration camps to be seen in/near Heidelberg?
The closest KZ (concentration camp, or german: Konzentrationslager) to Heidelberg is Natzweiler-Struthof about 50 km southwest of Strasbourg / France in Alsace (german: Elsass); that is approx. 180 km from Heidelberg in the Vosges Mountains. Although rather small compared to other KZs it’s still very impressive, and going there offers also a pretty scenic drive and the opportunity to stop at Strasbourg.