Hollowed out from the rock, this former phosphate mine is of interest on two counts. Firstly, it charts the history of the discovery and industrial extraction of phosphate and secondly, and above all, it is a genuine showcase of the megafauna of the Tertiary era (hyenas and giant felines, rhinoceroses, primitive horses, etc). Their fossils offer snapshots of the different epochs of this era. Reconstructed outlines of these animals are dotted about the site.