Yonaguni Monument

The Yonaguni Monument is a massive underwater rock formation off the coast of Yonaguni, the southernmost of the Ryukyu Islands, in Japan. There is a debate about whether the site is completely natural, is a natural site that has been modified, or is a manmade artifact.

The site is variably referred to as the "Yonaguni Underwater Formations" (与那国島海底地形Yonaguni-jima Kaitei Chikei^?) and the "Yonaguni Underwater Ruins" (与那国島海底遺跡Yonaguni-jima Kaitei Iseki^?) in Japanese.

Discovery

The sea off Yonaguni is a popular diving location during the winter months owing to its large population of hammerhead sharks. In 1987, while looking for a good place to observe the sharks, Kihachiro Aratake, a director of theYonaguni-Cho Tourism Association, noticed some singular seabed formations resembling architectonic structures. Shortly thereafter, a group of scientists directed by Masaaki Kimura of the University of the Ryūkyūs visited the formations.

The formation has since become a relatively popular attraction for divers in spite of the strong currents. In 1997, Japanese industrialist Yasuo Watanabe sponsored an informal expedition comprising writersJohn Anthony West and Graham Hancock, photographer Santha Faiia, geologist Robert Schoch, a few sport divers and instructors, and a shooting crew for Channel 4 and Discovery Channel. Another notable visitor was freediver Jacques Mayol, who wrote a book on his dives at Yonaguni.