Found­ed in the 11th and 12th cen­turies to serve the car­a­vans cross­ing the Sahara, these trad­ing and reli­gious cen­tres became focal points of Islam­ic cul­ture. They have man­aged to pre­serve an urban fab­ric that evolved between the 12th and 16th cen­turies. Typ­i­cal­ly, hous­es with patios crowd along nar­row streets around a mosque with a square minaret. They illus­trate a tra­di­tion­al way of life cen­tred on the nomadic cul­ture of the peo­ple of the west­ern Sahara.