Credit: Jean Denis Walter


The Yonaguni monument is one of the most mysterious and strange underwater structures, discovered in 1987 close to one of the Japanese Yaeyama Islands that holds the same name. Seen by many as an intricate artificial structure, the monument was challenged by skeptics, some of whom believe that it is merely an ordered stone formation that has developed naturally. Whatever its origins may be, the monument has stirred controversy in the archeological world, while putting the spotlight on Japan in the mid-1980s, when the underwater structures were discovered.

It is important, first of all, to note that the monument and other megaliths found off the coast of the island feature intricate geometric formations that many people believe couldn’t have formed naturally, without the aid of some form of intelligence. This is the consideration that has led to experts believing the structures are, in fact, artificial in nature. Including twin megaliths that are almost identical in shape and structure, and seem to have been secured in place by someone, the monument also features a trench with two internal 90 degree angles, suggesting that the stone was carved by humans. The debate continues on to this day, as other scientists believe the stone structures to be natural, being formed by earthquakes that are known to sever stones in a roughly ordered fashion.

The director of the local tourist association first discovered the monument in 1987, as he was searching for an appropriate underwater location for observing sharks. Since then, the formation, which was at first believed to be artificial in nature, became considerably popular, and divers from around Japan and the entire world continue to visit and study it. Although the strong currents in the region make it difficult for beginning divers to explore the site, a 1997 expedition and numerous tourists have led to a more thorough and controversial investigation of the monument over the next few years.

Made up of smooth medium sized sandstones and mudstones, the monolith is quite impressive to behold. The stones themselves are believed to be more than 20 million years old; however, the structure may be much younger than that. Placed at about 8 feet from the surface, the monument consists of straight walls, two closely spaced pillars, a triangular depression, a wide ledge and a star-shaped stone that is likened to a platform. The Yonaguni monument can be visited by skilled divers, having become one of the main attractions of the island.


Blane Perun

Diver - Photographer - Traveler

Whale in Ocean