Discovered accidentally by Japanese diver Kihachiro Aratake off the coasts of Japan

The resemblance to other megalithic structures has sparked theories suggesting they might be remnants of an ancient culture dating back to approximately 8,000 to 10,000 years ago.

The structure spans 120m in length, 40m in width, and stands 25m high, situated between two 8m high pillars (one shown in Pic.4).

The unique formation of the rocks that compose the structure has convinced many scholars of its artificial origin (a 3D reconstruction is shown in Pic.9).

A group of scientists, led by Professor Masaaki Kimura from Ryūkyu University, examined the remains and estimated that the rocks were excavated near the Ice Age, when the Yonaguni area was connected to a mainland bridge, including the islands of Taiwan and Ryūkyū.

Kimura and his team claim to have discovered at least 15 man-made structures off the coast of Yonaguni, including another structure, road links, aqueducts, and petroglyphs similar to those found in Okinawa, very close to Yonaguni.

Additionally, round stones believed to be part of a rudimentary system for draining rainwater are concentrated near grooves carved on the rock surfaces, presumably serving as gutters.

Other scholars, such as J.A. West and geologist R. Schoch (known for their belief in the Sphinx being 12,000 years old), suggest that the formation of the structure was a result of the erosion of rocks by the ocean and coral reef, attributing the structure to natural causes.

Despite the differing opinions, the precise cuts and steps, the stairway (Pic.7), and the triangular-shaped stone (Pic.6) present in Yonaguni tell a different story to Kimura and many others – one of a lost civilization that not only left these ruins but also other unexplained megalithic structures on Japan’s mainland.

What’s your take on Yonaguni – natural or man-made? Do you also notice the resemblance to the Sigiriya complex in Sri Lanka?