In the heart of Sorrento, behind central Tasso Square, lies an almost hidden treasure: an ancient and overgrown ruin in a lush ravine.

Sorrento’s coastline is pockmarked by valleys gouged out of the landscape by water thousands of years ago. One of the most striking ravines is in the center of town: Deep Valley of the Mills (Il Vallone dei Mulini). Located next to Piazza Tasso, it is a picturesque sight that is worth investigating.

The Deep Valley of the Mills forms the natural edge of the historic center of Sorrento. Narrow gorges have been cut through the valley by two streams: Casarlano-Cesarano and Saint Antonino. Look down to the floor of the narrow gorge and you’ll see an old flour mill, the structure that gave the valley its name.

A solid stone structure from the 900s, this mill was used for grinding wheat for nearly a thousand years before it was abandoned during the 19th century. At that time, the valley’s rising humidity level became a problem for the millers. The misty microclimate is perfect for fern growth the ruins’ roof is covered in a tangle of plants and branches, as if nature is trying to consume the building.

Attached to the grain mill was a sawmill for wood, supplying local cabinet makers. Look for remnants of a public washhouse, which had access to the trickling water from the slow streams. Imagine how the local women came here with their baskets full of clothing, enjoying the cooler climate in the valley.

Today, access to the valley floor is discouraged, so take in the views from street level high above. To see the ruins and vegetation in more detail, bring a set of binoculars with you or a camera with a good zoom lens.

A good position to view the Deep Valley of the Mills is from Via Fuorimura, which is a short walk from Piazza Tasso. One of the best times to come here is early to midmorning, when the light is still bright enough to see everything clearly. From noon onward the sun will cast shadows over the scene, making it harder to see. The ruins are lit up at night.