In 1985 Kihachiro Aratake, a dive tour operator from Yonaguni island (located at the end of the Ryukyu archipelago in the Southern part of Japan) was scouting for a new site to view hammerhead sharks. He found a megalithic structure that appeared to be man-made with expansive terraces interrupted by large angular steps and bounded by flat vertical walls. Further investigation revealed symmetrical and angular channels, round holes 7 feet (2 meters) deep, and angular raised platforms. The megalith was over 300 feet (100 meters) long.
In 1996 professor Masaaki Kimura, a geologist at the University of the Ryukyus on Okinawa, and his teams surveyed and documented the original structure. Since that time, several others have been found, but even after 15 years, Yonaguni’s true nature remains a mystery. To dive the monument is to go back to an age we know nothing about, it is a remnant of a prehistoric time. It may have been an ancient shrine (there are some structural similarities to ruins found on Okinawa), a quarry or a port, whatever it was, all we really know is that it’s there. Anything else is speculation.
More info on wikipedia.org/Yonaguni_Monument and morien-institute.org.
Why is it so hard for us to imagine that advanced civilizations are not a recent invention?