Yonaguni Monument: Ocean-Eroded Geometry, Not a Lost City
The Yonaguni Monument off Japan’s Yonaguni Island resembles a submerged citadel, but geologists say it’s a natural sandstone/mudstone formation shaped by fractures and erosion in an earthquake-prone area; while a small faction has claimed human modification, no archaeological evidence supports this, and ongoing surveys attribute the stepped blocks to natural tectonic and erosional processes.