One of the most striking and well known places of the Neapolis Archaeological Park is an artificial grotto shaped like an ear that's known as Orecchio di Dionisio. The cave is in the amazing area of the Gardens of Neapolis, with all kinds of plants and trees. The cave itself is impressive, both from the exterior and interior. On the outside, you can see the incredibly large opening in the rock, while inside there is a huge cavity that's 65 meters deep and 23 meters tall. I recommend bringing a flashlight because there's less light the further into the cave you go, and the last part can be difficult without a flashlight.