High above the Valtellina valley, hidden among the forests on the southern slope near Tresivio, lies Prasomaso. At the beginning of the twentieth century, this remote location was deliberately chosen for an ambitious and deeply human project: the construction of a sanatorium for tuberculosis patients, at a time when healing was sought mainly through rest, fresh mountain air, and sunlight.

In 1910, the Sanatorio Popolare Umberto I officially opened its doors. The imposing main building, designed by architects Diego Brioschi and Giovanni Giachi, stretched over more than one hundred meters and featured long sun-facing verandas. Here, patients spent hours lying in beds or resting in chairs, exposed to light and air as part of their therapy. The architecture was both functional and monumental, built around the belief that light, air, and order were essential to recovery. Demand quickly exceeded expectations, and the complex was expanded with additional buildings, including a sanatorium-school for children.

Prasomaso soon became a small, self-contained community. Patients often stayed for months or even years. Daily life followed a strict routine of rest periods, nutritious meals, medical checks, and quiet walks in the surrounding landscape. In an era before antibiotics, the sanatorium represented hope not only for healing, but also for dignity and care, accessible to people from all social backgrounds.

After the Second World War, medical progress changed everything. With the introduction of effective treatments for tuberculosis, the traditional sanatorium model gradually lost its purpose. Patient numbers declined, and by the second half of the twentieth century the complex was eventually closed. What had once symbolized medical progress and social commitment slowly fell into abandonment.