This system of waterfalls represents the remains of the sluice that used to feed an ancient mill owned by the Rasponi family, and dating back to the 12th century. A system of wooden bulkheads made it possible to raise the water level and convey it into a canal which, after passing in front of Palazzo San Giacomo, traveled several kilometers before forcefully operating the flour millstones. Known in the 1950s as the "beach of Bagnacavallesi", it was a meeting point for a refreshing swim, and still today it is a popular place for fishing or for pleasant walks. On the side of the Muraglione the communicating tanks of the "Ascent ladder" for fish fauna are visible, an artificial structure that allows the fish to overcome the difference in height created by the waterfalls. Along the river courses, where there are no barriers, the fish move from one place to another, depending on the season or the vital stage reached, in search of the best sites for the search for food and / or for reproduction. Just think of the great migratory birds such as eels, sturgeons or simply the numerous species that move for shorter distances, such as roach, chub or carp. However, when the watercourse is interrupted by dams and embankments, which constitute impassable barriers for the migration of fish species, "fish passages" can be created, fundamental works for maintaining the state of health of the rivers, as they restore the natural connection between the various river habitats.