At the Jagiellonian University's Collegium Maius, one of the finest examples of 15th-century Gothic architecture, visitors can take a guided tour (between 10am and midday) to view manuscripts written by renowned Polish astronomer and mathematician Nicolaus Copernicus and a selection of scientific books and instruments from the era. The awe-inspiring arcaded courtyard and clock (operational from 7am to dusk) can be admired, as well as a temporary exhibition exploring science.