This is a statue in the so Vari cave, an amazing site and ancient shrine to Pan. It was constructed (or more exactly carved) by the one man, Archedemos, who claimed that he was possessed by Nymphs. Here you see a statue, carved from the living rock.
An altar in at the same site, notice the ancient inscription.
Cape Sounion, I won't add much more as I very much believe that you need to take a look at this site by your own if it's new to you.