Orrido di Ponte Alto, Canyon with waterfalls in Trento, Italy.

The Orrido di Ponte Alto is a gorge about 100 metres deep cut by the Fersina torrent into walls of red scaglia rock, 10 to 15 metres wide in its middle and lower stretches. Below the Ponte Alto bridge stand two waterfalls formed by artificial dams, the Vecchia serra and the Serra Madruzzo. A partly covered guided route descends into the gorge, and a spiral staircase carved into the rock near the Serra Madruzzo dates from the second half of the 19th century.

The first works on the site date to the first half of the 16th century: in 1537 the prince-bishop of Trento, Bernardo Clesio, had a weir built to limit the damage that Fersina floods caused in the city. Two artificial weirs now stand below Ponte Alto, the northern Vecchia serra di ponte Alto and, a few metres south, the Serra Madruzzo. A spiral staircase cut into the rock near the Serra Madruzzo dates from the second half of the 19th century.

The name Ponte Alto comes from the bridge that crosses the gorge and links its two banks. The two artificial weirs below it, the Vecchia serra di ponte Alto and the Serra Madruzzo, were built from 1537 on the order of Bernardo Clesio, prince-bishop of Trento, to protect the city from Fersina floods. A spiral staircase cut into the rock in the second half of the 19th century is part of the guided route.

Access is through guided tours lasting around 45 minutes along marked paths within the gorge. Groups larger than 15 people should arrange visits in advance to ensure entry.

The long spiral staircase beside the Serra Madruzzo was cut directly into the rock in the second half of the 19th century and is now part of the guided route through the gorge. Look for the point where the water has exposed older rock layers, the Maiolica and Rosso Ammonitico, at the upstream base of the canyon.