I loved wandering around the Altstadt in Heidelberg!
The altstadt (old town) is the historic center of Heidelberg, and I found it to be very photogenic. It's a beautiful little town and I loved the streets, the cafes, shops and restaurants - all of it was nice. Though I was only there for 2 nights, I made the most of it, walking about 17,000 steps on day one! Yeah, I was tired though, so I found a place to enjoy a cold German beer. :-)