This grotto is a hidden treasure trove. No less than 20 petroglyphs and 472 pictograms dating from the Taíno period were discovered in the 1920s, depicting men, animals and ceremonies. These moving testimonies are enhanced by the beauty of the natural decor, composed of concretions that are reflected in the water and beautifully set off by special lighting effects. The grotto of marvels fully lives up to its name.