Built in 1589 to hold the art and fossils collection of the Borromeo Visconti Litta, the Ninfeo ("nymphs' cave") is an architectural oddity standing in the middle of a small park, separated from the main building of Villa Litta.

The strange structure of grotesques (halls built to resemble natural grottos) is composed of various rooms either, apparently carved in coral, or covered with frescoes and huge decorations made of coloured river pebbles. Greek-style statues abound in niches, on fountains and columns, and most of the decorations have mystical, alchemical or otherwise allegorical meanings.

When a local association began the restoration works in 1980 after centuries of abandonment and misuse, the Ninfeo revealed an unexpected and most unique surprise. The whole complex hides a wonderful array of hydraulical mechanisms built to amaze and delight the visitors! Undetectable pressure pads activated "naughty" jets of water, and hidden alcoves housed "fountaineers" whose job was to watch for cues from the owner of the place to start and stop "magic fountains" everywhere.

The difficult and still ongoing restorations have reactivated hundreds of spouts already, making dozens of wonders available again for the modern visitors. Today you can experience incredible "rainbow halls", sculptures animated by water, a strange-sounding water organ, several joke-spouts, rain chambers, fountains and more.

The Ninfeo is still a fragile thing, so you are advised to check the official website to visit on the few days of "full visits" where all the water wonders are actually working. A special treat are the summer nights in which the guides are dressed up with actual Renaissance garments: they will guide you through the various halls explaining the many intricate details both of the art and technology of this really unique place.