The Iron Tower (Eisenturm) is a medieval tower dating to the early 13th century, and modified in the 15th century, which with the Wood Tower and the Alexander Tower is one of three remaining towers from the city walls of Mainz, Germany. Its name derives from the Iron Market (Eisenmarkt), which was held in the immediate vicinity until the 19th century.
The Iron Tower served as a watchtower and gate to the city, and later as a gaol. It was badly damaged in World War II and reconstructed in the 1960s. Today it houses various organizations and art projects and is used for art exhibitions.
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.