Yonaguni

The Yonaguni Monument is an underwater rock formation off Japan's southern coast, often called a submerged "city" or "structure." Discovered in the 1980s, it features terraces, steps, and formations that resemble man-made architecture. Some believe it is the remains of an ancient civilization, while others see it as a natural geological formation shaped by natural processes like erosion and tectonic activity. Its mysterious appearance has sparked debate among archaeologists, geologists, and explorers, but its true origin—whether natural or man-made—remains a subject of ongoing research and fascination.