Tinnumburg is the best preserved of the three ancient ring forts in Sylt. The fort was built around the birth of Christ. The rampart has a diameter of 120 meters. The wall is up to seven meters high and has a circumference of about 440 meters. The castle had at least two gates (east and south).
Excavations in 1870, 1948 and 1976 provided evidence that the Tinnumburg was built in the style of early Roman Empire round ramparts on the North Frisian islands. The excavations have shown that this is a Germanic site of worship. The fort was in use again in the 8th to 10th centuries.
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.