If you walk along the Wadi Djerat in the Tassili n'Ajjer, on its left bank you come across a stone known only to the Tuareg. If you pick it up, you will see the carefully oiled imprint of a human foot underneath. For the blue men there is no doubt: this is the mark left by their oldest ancestor when he came to this land. To prevent the precious relic from weathering, each visitor reverently brushes it with oil and places the stone on it again (length 22 cm). - Algeria - 1962
