The "Shelter", as the locals called it, is decorated with stalactites and stalagmites, which change shape, depending on the inspiration of the visitor. It is located 171 meters above sea level, it is precipitous and its temperature in winter is 15 degrees Celsius. It has an area of about 5,600 square meters. Its maximum depth reaches about 85 meters and the descent is easy and safe, through a concrete staircase that numbers 411 steps. The exceptional visibility allows the observation of the detail of the artistic nature and the search of the human presence from the time of the Parisian poet Archilochus (728 - 650 BC) until the twentieth century.