Riou Island, south facade, Calanques National Park. Erosion has sculpted the limestone cliffs of Riou, giving them an almost "bony" appearance that evokes the age of the massif, of the order of 100 million years ... It is a rare image, because the the island is today very protected and it is forbidden to walk on it, to preserve the local flora and fauna. However, I had the chance to browse it, accompanying the teams of the Calanques National Park during various scientific follow-ups. This limestone, like a bone bleached in the sun, is made up of a mass of billions of organisms whose limestone skeleton was deposited at the bottom of an ocean a hundred million years ago ...