While it's not actually possible to go down into the valley, this long-forgotten mill is definitely worth viewing from the streets of Sorrento (it can be accessed just behind Piazzo Tasso).
According to historians, the valley was formed by a volcanic eruption thousands of years ago. Deep within it, you can see the remains of an old mill that was abandoned in the 1800s, left to succumb to the elements. The result is a group of stunning moss-covered structures that are like something from a post-apocalyptic world.
The magic of this valley is that if you don't know it was there, you just might miss it. When you visit, be sure to take your camera out to capture the otherworldly beauty of these buildings, which are now completely overgrown with lush greenery.
Throughout the Year
Valley of the Mills from above
Valley of the Mills