It seems that most every culture has a legend of a great society, ripe with wealth and wisdom, which is lost to the sea. To westerners these are the stories of Atlantis or Thule. To many of the peoples of the South Pacific it is Lemuria or Menehune. To Asians it is called Mu, and was home to people who could fly and who drank an elixir that would cease aging.
After years of searching, and combing the Pacific for a possible lost land that could have been the root of one of these legends, it is clear that there is no extra continent in the sea. However, in 1986, a SCUBA diver, Kihachiro Aratake, diving off the coast of the island of Yonaguni-jima discovered something that may lend credence to the existence of Mu or Lemuria. On the sea floor he found vast geometric structures cut out of the rock. There was evidence of stairs, and improbable angles in the stone. He marked the location for future divers, and in the intervening years these undersea ruins have come to be known as the "Yonaguni Monuments".
Efforts to date the monument are derived from the last time the area was above sea level, which would have been approximately 8,000-10,000 years ago-- about 3-5 millennia before Egypt's pyramids were erected. If the monuments were indeed built by humankind, it would require some dramatic revisions to the accepted chronological history of humanity.
Not far from a set of cliffs called "Iseki Point", the main structure of the Yonaguni Monuments lies under about two hundred feet of water. It is about 240 feet long, 90 feet wide, and 45 feet tall. There appear to be clear cut stairs, and to many there are distinct similarities to ancient buildings found on Okinawa, or even heiau temples on Hawaii. Various structures surround the main building, and they seem to stretch out into a road spanning approximately 311 miles leading to Okinawa and its neighboring islands.
But as clearly defined as the structures are to some, there are others who disparage the tale of the Yonaguni Monuments. No chambers or entrances have ever been found into the monuments, and no tools have been found in the vicinity to clearly indicate human involvement. Many assert that the formations can be attributed to erosion or coral settlements. The sharp angles and lines in the stone may be the result of the way the stones erode-- breaking off at right angles. One can look to the cliffs above the sea to observe that the regional stone tends to erode in a way that leaves naturally sharp angles.
Perhaps the most reasonable theory, however, is one which suggests that the mounds of stone are natural features that were carved and shaped into terraces by early man. This theory adequately explains the lack of entrance into the monuments, and the apparent post holes and etchings made in the rock.
Because of the submerged location and the strong currents in the area, the Yonaguni Monuments have proved difficult to properly study; though the area has become a popular site for SCUBA tours. Researchers have not yet found conclusive evidence implicating either erosion or humanity as the source of these shapes, so the investigation and debate regarding the nature of the Yonaguni Monuments continues.