Quattro Canti was laid out on the orders of the Viceroys between 1608-1620 by Giulio Lasso and Mariano Smiriglio at the crossing of the two principal streets in Palermo, the Via Maqueda and the Corso Vittorio Emanuele.
The piazza is octagonal, four sides being the streets; the remaining four sides are Baroque buildings, the near-identical facades of which contain fountains with statues of the four seasons, the four Spanish kings of Sicily, and of the patronesses of Palermo, (Christina, Ninfa, Olivia and Agata). The facades onto the interchange are curved, and rise to four floors; the fountains rise to the height of the second floor, the third and fourth floors contain the statues in niches. At the time the piazza was built, it was one of the first major examples of town planning in Europe.
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.