When scuba diving instructor Kihachiro Aratake plunged into the water off the coast of the Japanese island of Yonaguni in 1986, he discovered an incredible sight.
Six metres below the surface lay a series of monoliths that he described as appearing to be “terraced into the side of a mountain”. The huge rectangular formations had strikingly perfect 90 degree angles, including straight walls, steps and columns.
Over the following years experts descended upon the site in a bid to determine whether the structure was natural or man-made.
Yet to this day, it remains a great unsolved mystery. Initially it was proposed that the Yonaguni Monument was built when the area was above sea level some 10,000 years ago.
So could ‘Japan’s Atlantis’ be a remnant of a preglacial civilisation that was eventually inundated ? Or could it be the result of an earthquake, putting it at 2000-3000 years old ? Experts disagree.
As the structure was mapped out over the following years, more details came to light. Divers found what appeared to be a huge arch, as well as temples, carvings, paved streets and a large pyramid-like structure measuring 76 metres long at its base.