“Every year the whole community works together to replaster the mosque,” explains Fané Yamoussa, a local Malian historian. “We start at sunrise after morning prayers and by lunch it’s finished.” The dry months of January to March are the building season in Djenné, an ancient city in the Niger river’s vast inland delta. Its Great Mosque is the world’s largest mud building—and the reason for UNESCO naming the city as a world monument in 1988.
The minarets are 18 metres (59 feet) tall. The fortress-like walls are pierced with palm-wood beams. Every year in April, before the rains arrive, is the crépissage, when new mud is smeared over old walls. The city’s chief replasterers, some 80-strong, belong to a centuries-old guild called the barey ton. As one puts it, “a good mason knows the building and the spirits.”
Work must start only on an auspicious day, determined by star-gazing and religious debate (and when the mud in the river is the right consistency). The foundations are blessed amid secret prayers, a mixture of Koranic verse and local magical incantation. Rituals mark each building phase.
But the mason’s art is under threat. Young people prefer to make easier money as tourist guides or are leaving for the bustle of Bamako, Mali’s burgeoning capital. “Children today don’t want to be masons,” laments Mr Yamoussa. If the old knowledge is lost, his centuries-old mud city could disappear like a day-old sandcastle.