It is a fantastic dive site. Some they call it Abyss (dive site name), some they call it the Narkosis Theater and some they call it Horse Head. Only one thing I can tell It is really amazing. Only when you dive there you can understand what I mean.
Facts about Abyss Kythnos

• It is in Greece
• The typical depth is 0-50 Metres 0-160 Feet.
• The typical visibility is 30+ Metres 100+ Feet.