The Padua Astronomical Observatory, which is still located inside the Specola, is now one of the main research facilities of the National Institute of Astrophysics and has been producing high quality research at an international level for over two centuries. Since 1994 it has opened its oldest nucleus, the tower, to the city, transforming it into an astronomical museum.
The High Tower was actually built during the tyrannical reign of Ezzelino II da Romano, as part of the bastioned Castle he had created in 1242; the highest tower was in fact where he kept and tortured his prisoners. The Carraresi, who were lords of Padua in the fourteenth century, then used the ruins of the old castle as the basis for new fortifications, and embellished the building with splendid frescoes. In their day, therefore, the tower was one of the focal points of political, social and cultural life within the city. In the period of Venetian rule, the top of the tower become the Astronomical Observatory of the University of Padua (the section of castle alongside it being converted to a residence for the astronomer).
The new use was the result of recommendations to the Senate of the Venetian Republic from Giuseppe Toaldo, a monk and astronomer, and thus in 1777 the tower became known as La Specola, from the Latin Specula astronomica [Astronomical Observatory].
This new Observatory was one of the finest in eighteenth-century Europe and was visited by such illustrious figures as Johann Wolfgang Goethe, who in his 1786 account of his travels in Italy described the splendid panorama that could be enjoyed from the top of the tower. In the nineteenth century, the structure and equipment of the Specula underwent modernisation; a third cupola was added and a pavilion was erected on the adjacent tower to house the Mertz refractor.