In case you can arrange for it you may also want to visit Berlin. Since Berlin is vast (and flat) I would recommend you to rent a bike for 2-3 days. In my opinion the best way to get to know Berlin. Some highlights are listed -> here
My top 3 would be Hackesche Höfe, Museum Island and East Side Gallery.
I wish you a fantastic tour across Europe! Cheers!
Aww awesome! Okay I’ll keep that in mind when planning! :)