Wrocław University's baroque-rococo church is arguably the most beautiful in the city. It was built by the Jesuits in the 1690s on the site of the former Piast castle. Its spectacular interior, painted to give the appearance of white marble, is crammed with ornate fittings and adorned with fine illusionist frescoes of the life of Jesus. See the website for the church's somewhat convoluted sightseeing hours.