Ouadane or Wādān (Arabic: وادان‎) is a small town in the desert region of central Mauritania, situated on the southern edge of the Adrar Plateau, 93 km northeast of Chinguetti. The town was a staging post in the trans-Saharan trade and for caravans transporting slabs of salt from the mines at Idjil. A Portuguese trading post was established in 1487, but was probably soon abandoned. The town declined from the sixteenth century and most of it now lies in ruins.

The old town, a World Heritage Site, though in ruins, is still substantially intact, while a small modern settlement lies outside its gate.

Ouadane is the closest town to the Richat Structure, a massive circular landmark visible from space.

The early history of Ouadane is uncertain but it is possible that the town prospered from the trans-Saharan gold trade. In the middle of the 11th century, the Arabic geographer al-Bakri described a trans-Saharan route that ran between Tamdoult near Akka in Morocco to Aoudaghost on the southern edge of the Sahara. This route was used for the transport of gold during the time of the Ghana Empire. In his account al-Bakri mentioned a series of place names but these have not been identified and historians have suggested several possible routes.

In the 16th century the Moroccans made various attempts to take control of the trans-Saharan trade in salt and especially that in gold from the Sudan. They organised military expeditions to occupy Ouadane in 1543-44 and again in 1584. Then in 1585 they occupied Taghaza and finally in 1591 their victory in the battle of Tondibi led to the collapse of the Songhay Empire.

Tegherbeyat, the upper ruined section of the town, is almost certainly the oldest. It would have originally contained a mosque but nothing has survived. The ruins of the lower section of the town include a mosque that was probably built in the 15th century when the town expanded. Some of the horseshoe arches are still standing and some walls still have the remains of clay plaster, suggesting that the mosque was abandoned sometime in the 19th century.

The mosque measured 24 m north-south at its eastern end and 17 m north-south at its western end where the minaret would have stood. From east to west it would have measured 15 m. The terrace was supported by five rows of horseshoe arches. At the eastern end are the remains of an external mirhab and a courtyard measuring 13 by 12 meters that would have been used in hot weather.

Read more: https://en.wikipedia.org/wiki/Ouadane