Man-Made Or Natural? The Mystery Of "Japan's Atlantis"

Deep in the sea near Japan, lie the ruins of a city, built by a lost civilisation thousands of years ago. Called "Japan's Atlantis", the stone structures are situated in Yonaguni Jima, Japan's westernmost inhabited island, according to National Geographic. The ancient city was sunk by an earthquake 2,000 years ago, the outlet further said. It was rediscovered in 1987, when a local diver exploring off the coast of Ryukyu Islands spotted a series of almost perfectly carved steps with straight edges.

An old BBC report said that the rectangular, stacked pyramid-like monument is part of a long-lost Pacific civilisation, possibly built by Japan's prehistoric Jomon people who inhabited these islands as early as 12000 BC.

Some experts, however, compare it to Northern Ireland's Giant's Causeway, whose thousands of interlocking basalt columns (all natural formations) were created by a volcanic eruption millions of years ago.

The underwater structure has arched entrances, narrow passageways and is attached to a larger rock mass, said the BBC report.

"I'm not convinced that any of the major features or structures are manmade steps or terraces, but that they're all natural," Robert Schoch, a professor of science and mathematics at Boston University who has dived at the site, told National Geographic.

"It's basic geology and classic stratigraphy for sandstones, which tend to break along planes and give you these very straight edges, particularly in an area with lots of faults and tectonic activity," he added.

The structure has courted enough controversy about its origin, but neither the Japanese government's Agency for Cultural Affairs nor the government of Okinawa Prefecture recognise the remains off Yonaguni as an important cultural property.