Ponte del Diavolo, Natural sandstone arch in Polinago, Italy

Ponte del Diavolo, also called Ponte d'Ercole, is a sandstone monolith shaped into an arch about 33 metres long, located at Brandola in the municipality of Polinago. Its flanks are nearly vertical and its width runs from about three metres at the south-western end to less than one metre at the centre. At the northern end, a large basin was cut into the rock.

The arch formed through natural erosion over thousands of years, while the area has been visited by people since prehistoric times. Excavations have uncovered artifacts from multiple periods, showing that the location drew human activity across many centuries.

Local legend calls it Devil's Bridge because its natural formation seemed impossible without magic, though it was also linked to classical figures like Hercules and Apollo.

The arch can be reached by marked hiking trails starting from a parking area near State Road 12 heading toward Abetone. The path is clearly marked and guides visitors through the forest to the natural formation.

At the northern end, a large basin was cut into the sandstone itself, with a post hole at its base and three artificial holes in the walls; grooves at the openings show where water flowed. A quadrangular recess above one opening probably held a sluice board to regulate the outflow. The basin already appears in a 16th-century fresco at Castello di Spezzano.