The tower known as La Specola rises on the spot where Ezzelino III da Romano, the 13th-century tyrant of Padova, had built his fortified castle.
The present-day tower was erected in the 14th century, after the fort was rebuilt by Francesco I da Carrara. In 1767 the building was converted into an astronomical observatory (specula). In 1777 the tower housed a lower observatory, 16 metres above ground level, and an upper observatory at a height of 35 metres. The lower observatory was named the Sala Meridiana; noon was measured on the meridian line sunk in the floor. The upper observatory has walls of eight metres, and its large windows are almost six metres high.
The observatory remained in use until the 1930s, when the University decided to procure a large modern telescope; the site selected for the instrument was Asiago, on a plateau north of Padova, where the new structure was commissioned in 1942.