Benin Wall (9th century) – Nigeria
Constructed over a period of 600 years, the Great Walls of Benin was located at the southern border of the defunct Benin Kingdom, which was one of the oldest and most highly developed states in West Africa. The walls, which are four times longer than the Great Wall of China, are a combination of strong materials like ramparts and moats, which predated the use of modern earth-moving equipment and technology, and were used for defensive purposes
