A large rock on the bottom of the sea (18m meters deep), with quite a few holes to swim through (hence the name Graviera- cheese with holes- in Greek). Didn't see any special sea life, maybe because before us there was a guy spearfishing nearby. The light coming through the holes is something to remember, as you dive into darkness only to exit through light again. It is worth noting that although Naxos port is almost 2 miles away, the deep bass sound coming from the idling ferry engines is rather impressive and accompanies you through the dive. I used Nima Dive Center, who are professional as they are friendly and easy-going!