The Orecchio di Dionisio (Orecchio = Ear) is an artificial cave, funnel-shaped, carved in the limestone, which is about 23 m. wide and from 5 to 11 m. large, with a singular form, vaguely similar to an ear, which is almost 65 m. deep, with an unusual trend to S and with sinuous walls that converge at the top, in a singular sixth acute. The cave is also equipped with exceptional acoustic properties (sounds are amplified up to 16 times).
These acoustic characteristics and the form brought Michelangelo Caravaggio, who visited Siracusa in the 1608 with the famous citizen Vincenzo Mirabella, to name the cave Orecchio di Dionisio, giving strength to the legend according to which the famous sixteenth-century tyrant Dionysius had built this cave as a prison and there rinchiudesse his prisoners to ascoltere, from an opening above, the words magnified by the echo. In fact, even if at the expense of the suggestions and legend, you should know that the shape of the cave is simply due to the fact that the excavation started from the top, along the bottom shelf of an aqueduct winding, and was increasingly spreading in depth, having found a good quality of rock. To prove this on the walls are clearly observable traces of the working tools of the quarrymen and stone, in horizontal direction, plans detachment of the extracted blocks.