The Yellow Fortress or Yellow Bastion is a cannon fortress at the entrance of the 'Walled City of Vratnik'. It was built between 1727 and 1739 in area called Jekovac, close to the Jajce Barracks and the Jekovac water reservoir. It served as one of the defense points against the Austro-Hungarian troops in 1878. The fortress was damaged and rebuilt several times. The most recent renovation took place in 1998.
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.