Tuida was an early Byzantine and medieval fortress, the remains of which are located on the hill of Hisarlaka in the northeastern part of Sliven, which offers a unique view of the 'Sinite kamani' and the city. It is part of the old mountain fortification system, which played an extremely important role in the defence of the Roman Empire, and later of the early Byzantine Empire, as well as the medieval Bulgarian state. Tuida Castle was originally built in the 4th century AD and was in use until the 13th century.
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.