Plasencia City Walls were built in the late 12th century by Alfonso VIII of Castile, who founded Plasencia to protect his western border. The original perimeter was around 2.4 kilometers long. Towers with semicircular floors reinforced the walls and 26 of the original towers are still preserved. To visit the Wall of Plasencia visitors must stroll through the center of the old city and pass through any of the eight existing doors, gates and wickets. A walks through the barbican is an experience to enjoy.
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.