Speaker: Jean-Loïc Le Quellec, anthropologist, prehistorian, mythologist, Emeritus Director of Research at the Institut des Mondes africains (CNRS)

Since their discovery in 1850, the rock paintings and engravings of the Sahara have revealed a fascinating world. However, it wasn't until the 1950s that the general public was made aware of their existence, and learned of the disappearance of an ancient "green Sahara" which, today, is the stuff of dreams. In the central Sahara, on the decorated walls of the Tassilian plateau, representations of giraffes, elephants, crocodiles, rhinoceroses and hippopotamuses stand side by side with scenes illustrating the daily life of the vanished populations who bequeathed us these thousands of masterpieces. This collection bears witness to a radical climate change, on a scale comparable to the one that awaits us. Was this change abrupt or gradual? Do these images bear witness to the past of one or more civilizations? When did these civilizations live... and disappear? It's only in recent years that these images have really begun to reveal their secrets.