The Yonaguni Monument is a monolith just off the coast of Yonaguni. Discovered by local diver Kihachiro Aratake in 1987, it appears to have structures that have been carved into the rock. Masaaki Kimura of the University of the Ryukyus studied the underwater topography and came to the conclusion that rather than a natural formation, it is the remains of an ancient civilization that has otherwise been erased from history.

Divers enter through a short tunnel and then find two columns that reach up to near the surface.

Yonaguni Monument - Couple Stones

Divers then make their way around the loop road to the lower and upper terrace. The rock has been cut / fractured at right angles, with step like structures between levels.

Yonaguni Monument, Okinawa - Upper Terrace

A triangle shaped pool may have once been the foundations for a building. Holes in the edges of the triangle could have been used to hold the main uprights.

Yonaguni Monument, Okinawa - Triangle Pool

And finally you reach the turtle sculpture. I had been expecting it quite small so I was surprised to find it close to 10 meters across. This was why in the images I wanted to have a diver in the shot (Kihachiro Aratake’s son Shotaro) to show the scale.

Yonaguni Monument, Okinawa - Turtle Sculpture

After each dive there is a friendly discussion about whether the ruins are natural or manmade. My opinion is that they’re natural, but many others were sure that we were looking at some version of Atlantis created thousand of years ago by a lost civilization, or even aliens.