The Yonaguni Monument, also known as the Yonaguni Submarine Ruins, is a fascinating and controversial underwater rock formation located off the coast of Yonaguni, the westernmost inhabited island of Japan. This unique and enigmatic structure has sparked debate and intrigue among archaeologists, geologists, and researchers since its discovery in the late 1980s.

The Yonaguni Monument consists of massive stone formations, terraces, and pillars that resemble architectural structures, including steps, platforms, and columns, some of which are arranged in a manner that suggests intentional design rather than natural formation. The most prominent feature of the monument is a massive rock formation known as the "Main Platform," which measures about 100 meters in length and stands about 25 meters tall.

Several theories have been proposed to explain the origin and purpose of the Yonaguni Monument. Some researchers believe that the rock formations are natural geological structures that have been sculpted and eroded by the forces of nature over thousands of years. According to this theory, the unique and intricate patterns of the rock formations are the result of tectonic activity, erosion, and weathering processes.

On the other hand, some experts and researchers argue that the Yonaguni Monument may be the remnants of a prehistoric or ancient civilization, possibly dating back to the last Ice Age or even earlier. Proponents of this theory point to the symmetry, alignment, and positioning of the rock formations as evidence of human intervention and intentional design. They suggest that the monument may have served as a ceremonial site, a religious temple, or even a part of a lost civilization that inhabited the region thousands of years ago.

Despite ongoing research and investigations, the origin and purpose of the Yonaguni Monument remain a subject of debate and controversy, with no definitive conclusions reached to date. The site has become a popular destination for scuba divers, researchers, and tourists interested in exploring the mysterious underwater formations and experiencing the unique marine life and underwater landscapes of Yonaguni.

To preserve and protect the Yonaguni Monument and its surrounding marine environment, the site has been designated as a Marine Protected Area, and strict guidelines and regulations are in place to ensure responsible tourism and conservation efforts.