The Calamai Wool Mill is an icon of Prato's industrial architecture. It stands along one of the most important roads that lead from Prato towards the Bisenzio Valley and up to Emilia Romagna, namely Viale Galilei. Situated outside the ancient fourteenth-century walls, it enjoys an exceptional strategic position, dominates the view along the Bisenzio river and is located a short distance from the Prato Porta al Serraglio train station, with which it was connected directly via a building now demolished. From the factory gates you can admire a unique panorama: the Bisenzio river and the hills surrounding the city.

The structure of the wool mill is of considerable size, measuring approximately 16,000 square metres, and has a functional layout of the rooms still used today for various processes. The warehouse pavilions are covered by shed roofs and create a harmony of symmetrical volumes. Outside the building is striking for its grandeur and for the monumental entrance, included among the city architectures that deserve to be preserved. Inside, the functional structures with large spans supported by light reinforced concrete beams and pillars, dating back to 1924, are attributed to the Poggi and Gaudenzi company, for which the young engineer Pierluigi Nervi worked, and for this reason cited in many architectural studies.

On one side of the former factory there is a mural by the artist DEM which interacts with the architectural complex, exploiting its shape and creating a contemporary polyptych connected to the Metastasio Theatre, entitled "Observing the world through other people's eyes".