Took the train from Frankfurt Hauptbahnhof, direct, for 22 euro. I have a bahn card 50%, so it was only 11 euro for me, one way. Train took 50 min. At the Heidelberg Hbf. we caught a tram that took us to the alt stadt. Here we took the funicular up to the castle. What fun!
I like the castle here. It is quite massive and if you spend some time walking around looking at all of it, and learn a bit about what and why it was built, then it is a lot more interesting. Have been here many times, but I always enjoy seeing the tower all tumbled down. The view from the terrace of the castle is stunning. Sadly, because it is Jan. the gardens aren't very pretty, but in the spring and summer they are gorgeous.
Then, we went into the medieval pharmacy. This is very well done and worth a stop. After that, we of course went down to the giant wine barrel. It truly is huge. Normally, I would walk down the path to the Alt Stadt, but it was drizzling and didn't look very inviting, so we went back down with the funicular.
Headed over to the church, admiring the architecture of the Alt Stadt. Some really pretty buildings and wooden doors. The church has a lovely painted ceiling up around the vaulting. One of the more interesting things here is that it was shared by Catholics and Protestants. They had a wall that went through the church and separate entrance and exit doors. One of the modern stained glass windows depicts Hiroshima, with the date of the bombing. Kind of an odd choice for a church.
Then off to the Student Prison. I had not seen this on any of my other trips here, so was excited to finally go here. What a fascinating place. I doubt there is anything remotely similar any place else. This was my favorite thing to see in Heidelberg. After we had looked around for quite awhile, reading names, dates, and quotes we went to see the old Aula. This is like a lecture hall, but very elegant, painted ceilings, lots of dark wood.
We strolled some more around the Alt Stadt, before heading back to Frankfurt. Lots of unique little stores, cafes and pubs, so something for everyone. I enjoyed the architecture a lot, and it was fun to be in such an old university town, with so many old traditions. For anyone unsure about whether or not they should visit Heidelberg, my advice is to go.