Krakow is a big university town, with lots of unis and lots of students. It is somewhat rare to meet someone in Kraków under in their 20s that didn't go to university / isn't currently at university. There are normally around 140,000 students in all of Krakóws universities at any one time.
For a larger list, see here.
Read our famous and comprehensive guide to everything you need to know before vistiing Kraków!
Read about exploring the abandoned Liban Quarry (and ex Nazi labour work camp)