The Piscina Mirabilis was a freshwater cistern on the Bacoli cliff at the western end of the Gulf of Naples. One of the largest freshwater cisterns built by the ancient Romans, it was situated there in order to provide the Roman western imperial fleet at Portus Julius with drinking water.
The cistern was dug entirely out of the tuff cliff face and was 15 metres high, 72 metres long, and 25 metres wide. It was supported by vaulted ceilings and a total of 48 pillars. It was supplied with water from the main Roman aqueduct, the Aqua Augusta, which brought water from sources in Serino near Avellino, 100 kilometres distant, to Naples.
The ancient cistern is currently in private hands, but parts of it may still be visited by the public.
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.