Leuchtenberg Castle was built around 1300 by the landgraves of Leuchtenberg, an influential medieval aristocratic family. Presumably there was already a fortification on the hill before. The noble family died in 1646. After the death of the last landgrave, the castle deteriorated rapidly, in 1842 it was completely destroyed in a major fire.
In the 20th century the castle ruins wer restored and today it is used as an open-air stage and is the venue of the annual castle festival Leuchtenberg.
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.