The Great Mosque of Djenné is the world’s largest mud structure – yes, it’s made from mud – and the third one built on the same site. The first one was constructed in the early 13th century and became a religious center for the ancient pilgrimage city of Djenne, which served to spread Islam within Africa.
It’s made of earth bricks that have been dried in the sun, mortar made of sand and a plaster that creates a smooth surface. Every year, the people of Djenné have a festival where they work together to fix any parts of the mosque that need repairs.