Krakow is a truley stunning place, the main square and the Wawel are lovely and it is worth the time to wander around the Jewish quater aswell much better than Pragues. The night life here is also astounding (i honestly never thought i would say that about Poland!) try some of the many bars in caves around the main sqaure especially CW Bruwar, which sells beer by the metre!! Krakow also makes a great base for exploring the other nearby sites on the UNESCO list Auschwitz Birkenau, and the Wieleczka Salt mines both a short train ride from the main station.