Unlike the towering pyramids of Egypt, this monument was flat-topped and hexagonal, with rows of precisely placed megalithic stones forming its foundation. Archaeologists believe that the shape ...

A hexagonal stone from the Iwatsuki Castle ruins measured 4.8 centimeters in diameter and 1 cm thick, while 17 stones from the Owada jinya measured 8 to 14 cm in diameter and 1.5 to 3 cm thick.