The structure, which cannot be seen from land, is massive — about twice the diameter of Stonehenge.
Further study by a team of scuba-diving investigators revealed that the boulders are made of basalt and have no decorative chiseling or cutting. Individual boulders are as big as 3 feet across, and the lower half of the structure is covered by sand.
They also noted that nothing was growing on the boulders and that the rocky area was teeming with tilapia, which may like using the rocky crevices to hide in.
Story: Deborah Netburn, LA Times | Photo: Shmuel Marco, International Journal of Nautical Archaeology