In the town of Djenné, in Mali, there is a building made almost entirely of mud.
That might not sound very grand. But it is enormous. It has three tall towers, each topped with an ostrich egg, and walls that are warm brown and as thick as a car is long. It is the biggest mud building anywhere in the world.
Sticking out of the walls, all over, are hundreds of wooden poles. They look like spines on the back of a friendly creature. They are not decoration. They are a ladder.
Because here is the thing about mud: rain washes it away. Every year the rains come, and every year the great mosque loses a little of itself.
So once a year, the whole town fixes it.
It begins before sunrise. Boys race to the river for water. Older men mix the mud with rice husks and shea butter in big pits, stirring it with their feet. Women carry the mud to the walls in bowls balanced on their heads. Then the men climb the wooden poles and press it on by hand, smoothing it with their palms.
There is music. There is a great deal of shouting and laughing. By the end everyone is covered head to toe.
And the mosque stands up new again, smooth and brown, ready for another year.
It has been done this way for hundreds of years.
Goodnight, Djenné. Sleep well.



