The Nervion River makes its way between huge walls of limestone rock, where it has created the ideal habitat for the griffon vultures. In its vertical walls the nests of vultures are very numerous and during the mating season, they fly around the huge waterfall, making to all tourists enjoy with their great power, leaving no one indifferent. A spectacle for the eyes to see more than 100 vultures rise from the bowels of the canyon and end up flying over the incredible Sierra Salvada natural park. That day, a winter day in february, the griffon vultures were preparing the nests, making numerous flights with branches to accommodate it, crossing the canyon and ascending to the surface several hundred meters high, passing a few meters from the dozens of people who visited the waterfall that day.