Taoudenni (also Taoudeni, Taoudénit, Taudeni, , ) is a remote salt mining center in the desert region of northern Mali, north of Timbuktu. It is the capital of Taoudénit Region. The salt is dug by hand from the bed of an ancient salt lake, cut into slabs, and transported either by truck or by camel to Timbuktu. The camel caravans (azalai) from Taoudenni are some of the last that still operate in the Sahara Desert. In the late 1960s, during the regime of Moussa Traoré, a prison was built at the site and the inmates were forced to work in the mines. The prison was closed in 1988. Salt mining The earliest mention of Taoudenni is by al-Sadi, in his Tarikh al-Sudan, who wrote that in 1586 when Moroccan forces attacked the salt mining center of Taghaza (150 km north west of Taoudenni) some of the miners moved to 'Tawdani'. In 1906 the French soldier Édouard Cortier visited Taoudenni with a unit of the camel corps (méharistes) and published the first description of the mines. At the time the only building was the Ksar de Smida, which had a surrounding wall with a single small entrance on the western side. The ruins of the ksar are 600 m north of the prison building. The Taoudenni mines are located on the bed of an ancient salt lake. The miners use crude axes to dig pits, which usually measure 5 m by 5 m with a depth of 4 m. The miners first remove 1.5 m of red clay overburden, then several layers of poor quality salt before reaching three layers of high quality salt. The salt is cut into irregular slabs that are around 110 cm x 45 cm by 5 cm in thickness and weigh around 30 kg. Two of the high quality layers are of sufficient thickness to be split in half, so that 5 slabs can be produced from the three layers. Having removed the salt from the base area of the pit, the miners excavate horizontally to create galleries from which additional slabs can be obtained. As each pit is exhausted another is dug, so there are now thousands of pits spread over a wide area. Over the centuries salt has been extracted from three distinct areas of the depression, with each successive area located further to the south west. The three areas can be seen clearly