I just went to Prague. It is an amazing city, I'm so glad i went. We signed up for a walking tour online and it just so happened we had a tour guide all to ourselves. We went on his tour of the Jewish quarter the next day and had him to ourselves then too! I learned a lot about Eastern European history, architecture, and Jewdaism.
We also went to the Czech National Opera and saw a Dvorak opera. We had a box to ourselves. It was magical.
the only thing I would do differently, is plan an excursion outside of the city. It was packed with tourists and would have been nice to get away.