Yonaguni May Be Natural Terrain Modified by Ancients

Off Japan's Yonaguni Island lies large rock formation at 25 m depth. Structure has flat planes, broad steps, near-right angles, long grooves. Since diver discovery in 1980s, called Yonaguni Monument.

Off Japan's Yonaguni Island lies large rock formation at 25 m depth. Structure has flat planes, broad steps, near-right angles, long grooves. Since diver discovery in 1980s, called Yonaguni Monument.

Off Japan's Yonaguni Island lies large rock formation at 25 m depth. Structure has flat planes, broad steps, near-right angles, long grooves. Since diver discovery in 1980s, called Yonaguni Monument.

Off Japan's Yonaguni Island lies large rock formation at 25 m depth. Structure has flat planes, broad steps, near-right angles, long grooves. Since diver discovery in 1980s, called Yonaguni Monument.