Is the breathtaking stone structure the work of a 10,000-year-old civilization, or is it somehow an illusion? Atlas Obscura explains:
The Yonaguni-jima Kaitei Chikei, literally translated as “Yonaguni Island Submarine Topography,” is an underwater mystery off the coast of the Ryukyu Islands, Japan. The massive underwater rock formation is speculated to have existed for more than 10,000 years, but whether the formation is completely man-made, entirely natural, or merely altered by human hands is still debated.
The monument was first discovered in 1986 by a diver. Masaaki Kimura, a marine geologist at the University of the Ryukyu, explored the monument for nearly two decades. Kimura remains convinced that the site was carved thousands of years ago, when the land mass was above water.
According to Kimura, the Yonaguni’s right angles, strategically placed holes and aesthetic triangles are signs of human alteration. He also claims that carvings exists on the monuments, resembling Kaida script.