Yonaguni Monument/ Underwater Ruins

The Yonaguni Monument lies off the southern coast of Yonaguni Island, the westernmost inhabited island of Japan, in the East China Sea near Okinawa. The site is a large submerged rock formation of terraces, flat planes and sharp edges discovered by divers in the 1980s, which has fueled ongoing debate over whether it is a natural geological feature or a shaped, man-made structure. It sits at depths of roughly 5 to 25 metres, with strong currents in the surrounding waters that draw divers to the area partly for the formation and partly for seasonal hammerhead shark sightings nearby. Diving here is generally considered for those with some experience, given the current and the exposed, open-water location off the island's coast.