The thing I like most about organized journeys is that one not only goes around sightseeing, but due to the lectures of the professional guides one gets to experience personally the geography and the history of the place.
I loved Cesky Krumlov - the castle, the towers, the narrow cobbled streets and the beautiful houses. We were in luck - there was a medieval festival held in the central square of the town and we were able to look at (and buy) articles of artisan crafts and taste traditional meals, sweets and of course, beer. You haven't been to the Check republic if you haven't drank lots of local beer :))
After visiting Krumlov, we traveled to Hluboka castle - a Gothic castle, built in the 13th century, later extended and reconstructed throughout the centuries into Renaissance and Baroque styles. It's truly magnificent and worth visiting.