Across the Sahel, builders perfected a monumental architecture in sun-dried earth, using moulded mud bricks rendered in banco plaster over timber armatures. Projecting palm-wood beams (toron) act both as decoration and as permanent scaffolding for the annual community re-plastering that the climate demands. The Great Mosque of Djenné, the largest mud-brick building in the world, embodies the tradition; its tapering buttressed walls and pinnacled towers define the Sudano-Sahelian style. The whole town of Djenné is built in the same material and is collectively maintained.
Sahelian earthen construction is a sophisticated, climate-adapted and communally maintained urban building system, giving West African cities a distinctive and enduring monumental architecture.