Medieval-style fortifications are back in the Sahel
Newly walled towns are a sign of shrivelling state authority
Double berm or raised fortification, Kauwa, Nigeria Photograph: Google Earth/Google Maps/Courtesy Olivier Walther and Steven M Radil
Not much remains today of the walls, ramparts and moats that once surrounded Benin City in southern Nigeria. Yet for centuries these giant earthworks—second in length only to China’s Great Wall among man-made structures—bespoke a mighty civilisation whose authority extended across much of west Africa. By the standards of pre-colonial Africa, the Benin state was exceptionally strong: erecting the wall in a single dry season might have required mobilising as many as 5,000 men, each working ten hours a day. But as the empire withered and eventually succumbed to British invaders in the late 19th century, most of the earthworks vanished. So did those of many other fortified towns across west Africa.
