The historical setting
The Great Mosque of Djenné in the Sudano-Sahelian architectural style is the largest adobe brick building in the world. The mosque is located in the city of Djenné, Mali, on the flood plain of the Bani River. The first mosque on the site was built around the 13th century, but the current structure dates from 1907. As well as being the centre of the community of Djenné, it is one of the most famous landmarks in Africa. Along with the "Old Towns of Djenné", it was designated a World Heritage Site by UNESCO in 1988. The actual date of construction of the first mosque in Djenné is unknown, but dates as early as 1200 and as late as 1330 have been suggested. The earliest document mentioning the mosque is Abd al-Sadi's Tarikh al-Sudan which gives the early history, presumably from the oral tradition as it existed in the mid-seventeenth century.
Present mosque
In 1906, the town arranged for the original mosque to be rebuilt and for a school to be constructed on the site of Seku Amadu's mosque. The rebuilding was completed in 1907 using forced labour under the direction of Ismaila Traoré, head of Djenné's guild of masons. From photographs taken at the time, it appears the position of at least some of the outer walls follows those of the original mosque but it is unclear whether the columns supporting the roof kept to the previous arrangement. What was almost certainly novel in the rebuilt mosque was the symmetric arrangement of three large towers in the qibla wall.
There has been debate about to what extent the design of the rebuilt mosque was subject to French influence, although it is unlikely that French engineers worked on the building at all. Dubois revisited Djenné in 1910 and was shocked by the reconstructed mosque. He believed that the French colonial administration were responsible for the design and wrote that it looked like a cross between a hedgehog and a church organ. He thought that the cones made the building resemble a baroque temple dedicated to the god of suppositories.
Design
The walls of the Great Mosque are made of sun-baked earth bricks (called ferey), and sand and earth-based mortar, and are coated with a plaster which gives the building its smooth, sculpted look. The walls of the building are decorated with bundles of rodier palm (Borassus aethiopum) sticks, called toron, that project about 60 cm (2.0 ft) from the surface. The toron also serve as readymade scaffolding for the annual repairs. Ceramic half-pipes also extend from the roofline and direct rain water from the roof away from the walls. The mosque is built on a platform measuring about 75 m × 75 m (246 ft × 246 ft) that is raised by 3 metres (9.8 feet) above the level of the marketplace.
The platform prevents damage to the mosque when the Bani River floods. It is accessed by six sets of stairs, each decorated with pinnacles. The main entrance is on the northern side of the building. The outer walls of the Great Mosque are not precisely orthogonal to one another so that the plan of the building has a noticeable trapezoidal outline. The prayer wall or qibla of the Great Mosque faces east towards Mecca and overlooks the city marketplace.
Cultural significance
The entire community of Djenné takes an active role in the mosque's maintenance during an annual festival. This includes music and food, but is mainly to repair the damage inflicted on the mosque in the past year (mostly erosion caused by the annual rains and cracks caused by changes in temperature and humidity). In the days before the festival, the plaster is prepared in pits. It requires several days to cure but needs to be periodically stirred, a task usually falling to young boys who play in the mixture, thus stirring up the contents. Men climb onto the mosque's built-in scaffolding and ladders made of palm wood and smear the plaster over the face of the mosque.
Another group of men carries the plaster from the pits to the workmen on the mosque. A race is held at the beginning of the festival to see who will be the first to deliver the plaster to the mosque. Women and girls carry water to the pits before the festival and to the workmen on the mosque during it. Members of Djenné's masons guild direct the work, while elderly members of the community, who have already participated in the festival many times, sit in a place of honour in the market square watching the proceedings.