From 800AD to 1460AD, Benin City built defensive walls, with a combination of ramparts and moats. The ramparts were up to 66 feet high, and covered 9,950 miles, and an area is 2,317 square miles. It was considered the world’s largest earthwork, constructed of a ditch and dike structure. It was recorded in the Guinness Book of World Records in 1974.
For defensive measures, the king, Oba Oguola, (1280-1295) constructed 20 smaller moats around important towns and villages. Oba Ewuare the Great (1440-1473) built an 2000 mile extension, and installed 9 gates at the entrance, which were heavily guarded. This prevented invaders and slavers from getting access into the city, in addition, trespassers risked being hit with spears, being buried in sand avalanches, and falling into the deep moats. Learn more about the Benin City and its walls here.