The 16th-century Renaissance building was once home to the office of the Polish astronomer and city councillor Johann Hevelius, whose statue can be found in the park in front of the building. The former headquarters of the Council of Gdansk, the Old Town Hall served as the headquarters of the Soviet Army during the dying days of WWII, probably because it was practically the only building left standing in the city at the time. Today the building is open to the public and has become the focus of much creativity. There's also a cellar restaurant, and a good bookshop on the ground floor.
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.