Entering the Torre della Specola, we come to what is known as the Sala dell'Iscrizione. This area of the building owes its name to a plaque that recalls how the trapdoor in the floor was the entrance, still visible today, to the infamous prisons built by Ezzelino, consisting of two windowless rooms with no way out. It is said that even the architect Zilio, after the construction of the tower was finished, was locked up and left to die here so that he could not reveal any of the building's secrets.