This huge tomb, located in the Osaka area near the city of Sakai, is the largest in Japan and covers nearly 80 acres. It is over 1300 ft. long, nearly 100 ft. high and is surrounded by a three-ringed moat. According to the Japanese Imperial Household Agency, it was conceived and built by emperor Nintoku, who reigned, according to the Nihon shoki from 313 to 399. But archaeological evidence suggests it was built in the 400s, and may be associated with the reign of emperor Yūryaku (456-479 CE).