We headed straight to the schloss! Heidelberg is lovely. Also, it has an incredible history. Two thumbs up. I am a lucky human.
It got sunny:
Apothecary museum (Free entry!!):
Mark Twain spent time in Heidelberg and wrote about this GIGANTIC wine cask in his book, A Tramp Abroad:
And there was a students’ prison. Yes, prison for students. That was a real thing until 1914. Mark Twain wrote a funny dialogue about it. :