布拉格 is the most beautiful city in Europe (my opiniion).
I've visited there twice. Scene was as wonderful as before. However, I met theives and robbers in both experience. Be careful.
Czech is a nice place to go. How many days would you stay?
Prague should be the first city you arrived. And you should go to other cities also if you have time, like Kalovy Vary. It is a place with hot springs.
You should buy a rail pass so that you can go to other cities very conveniently.