L'infinita Fabbrica del Duomo tells the story of the birth and the ongoing maintenance of the Milan Cathedral through the centuries. First act of the tetralogy "Spira Mirabilis" which deals with the concept of immortality through the elements of nature, L‟infinita Fabbrica del Duomo represents the element of the earth. Through a poetic perspective and a strong visual impact, the film follows the stages and the work that the preservation of the Cathedral requires: from the extraction of marble, to the marble yard, the Historical Archives, the Cathedral itself. Stonemasons, bricklayers, carpenters, blacksmiths, restorers, goldsmiths: this extraordinary, but steady, concentration of activity is filmed in relation with the sanctity of a monument that lives times, rhythms, calendars, aspirations that transcend the human labor and takes a new symbolic value.