The Cathedral Basilica of the Holy Cross (Bazylika Katedralna Podwyższenia Krzyża Świętego) was built in the 15th century on the site where before there was a structure of the 11th and 13th centuries. It was rebuilt several times. With towers with a height of 73 meters is the tallest structure in the city. In the temple there is a painting of the Virgin of Opole, brought there permanently in 1702.
References:The Clementinum is a historic complex of buildings in Prague. Until recently the complex hosted the National, University and Technical libraries, the City Library also being located nearby on Mariánské Náměstí. The Technical library and the Municipal library have moved to the Prague National Technical Library at Technická 6 since 2009. It is currently in use as the National Library of the Czech Republic.
Its history dates from the existence of a chapel dedicated to Saint Clement in the 11th century. A Dominican monastery was founded in the medieval period, which was transformed in 1556 to a Jesuit college. In 1622 the Jesuits transferred the library of Charles University to the Klementinum, and the college was merged with the University in 1654. The Jesuits remained until 1773, when the Klementinum was established as an observatory, library, and university by the Empress Maria Theresa of Austria.