Centers of Learning in Ancient and Medieval Times?

Question

Can you name some centers of learning in ancient and medieval times,like places that scholars from all over the world traveled just to study there?And why did they travel there?

Answer 1

in the ancient times Alexandria and Athens were the centers of learning, in the medieval times Baghdad, Cairo and cities of Spain were the centers of knoledge,  

Answer 2

Alexandria, Egypt (the mathematician Hypatia was killed there in 415 AD for being a pagan and the library was burned for the final time)

"To teach superstitions as truth is a most terrible thing."  --Hypatia, c415 AD

Cordova, Spain  (1100-1300 AD).  Cordova had a university and a library with over a million books in six languages.   Women were allowed to attend the colleges.  They also had lighted streets and flush toilets.    The library was burned by Christians when they retook the city from the Moors.  

"Reserve your right to think, for even to think wrongly is better than not to think at all."  --Hypatia, c. 415 AD.