Niederkastenholz castle is surrounded by a moat, with an angular main castle and a separate horse-shoe shaped fore-castle with working quarters. It used to belong to Kornelimünster Abbey. The rough stone buildings of the castle are complemented by the wrought-iron gate. The fortified tower dates back to the 12th century and is the oldest part of the castle.
The so-called Probstei was added onto the medieval main castle between 1752 and 1756. Part of the moat is still visible today, although most of it was filled in during the 19th century.
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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.