The main courtyard is well visited by groups especially on the hour when the clock doors open and music is played whilst models of important figures walk around on a platform. The other courtyard is a lovely place to sit with statues and scientific instruments. The library visit is very good, 1 hour is best to see all the old scientific instruments etc. but you can go in on your own for free on Wednesday afternoon between 3 & 6pm. Well worth a visit to this historical university.