Aquis Querquennis is the ruins of a Roman military camp sit along a flooded section of a river. The construction of the barracks dates back to the reign of Vespasian, around the year 75, when it was likely used as a base from which to defend newly built roads connecting other, larger roads in this remote province.
The walls, arches and moat that form the foundations of this former Roman military camp can sometimes be found half submerged in the reservoir, depending on the amount of rain upriver and the status of the dam.
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.