Travel / What is "must-see" in Poland? [8]

Merged: Visiting Poland early next year, what to do, what to see?

It will be my first time in Europe as all of my previous traveling experience has been in Latin America. I'm in my early mid-20's and am spontaneous when I travel. I don't like to have a plan; just a general idea of what I may or may not do. It will be a two-week vacation and I'm thinking of arriving in Krakow. I do enjoy nightlife but I also like to meet the locals and explore the city.

I'd like to visit at least two cities in Poland, the other being Warsaw and possibly one more but I don't think I'd have the time. Would two-weeks be too much or too little for Krakow and Warsaw? Also, as the thread title mentioned: What should I do? What should I see?

Thank you!