They are also the very rare sites in Burkina Faso to have furnaces in elevation. Criterion (iii): The ancient ferrous metallurgy sites bear exceptional testimony to a unique tradition of iron ore smelting, passing on to today’s Burkina Faso communities a rich technical and cultural heritage. Tiwêga, Yamané, Kindibo and Békuy are massive production sites that illustrate iron production throughout the Sahelian zone of Burkina Faso in the second millennium AD. Criterion (iv): The ancient ferrous metallurgy sites are outstanding examples that illustrate the variety of traditional iron ore smelting techniques in Burkina Faso. Criterion (vi): The ancient ferrous metallurgy sites of Burkina Faso are directly associated with living traditions embodied by the socioprofessional group of the blacksmiths.