A project founded on the idea of the grand spectacular decoration, a recurrent idea in Ponti's work. «The location does not permit frontal views, hence an architecture that exploits the effects and surprises of foreshortened views. Inside this «citadel of political thought, the project functions on two distinct levels or registers: first, the «register of honor» (portal of honor, court of honor, staircase of honor, hall of honor, and there is even an elevator of honor) so that visitors from all over the world will pass through the monumental halls, as happens in the Vatican and in ancient palaces; and the register of service.

There are many inventions (amusement suited Ponti better than the monument) in the honor suite: the portal of honor, taking up the whole height of the building, is set back from the facade (it comes as a surprise); the hall of honor has a marble-inlay floor, an immense, colored carpet of marble, and visitors gaze down upon it from a white marble step around the edge; the court of honor has a Colonnade in perspective consisting of eighty-four columns (each made of a different kind of marble) in diverging rows that descend toward the garden; in the garden, enclosed by the Aurelian walls, spectacular displays of water and light are staged in the ancient Italian manner. The artists invited to provide frescoes and sculptures were Funi and Martini. The register of service has dictated the layout: there is also a shelter, where the Ministry can carry on its functions underground, a small but perfect sunken ministry; here too, the plants are a spectacular complex, accessible to the public.

The project lost the competition. Gio Ponti entered it with his Studio (then the Studio Ponti Soncini), the Studio Ulrich and the Studio De Carli, Angeli Olivieri,  Piero Fornasetti and Enrico Ciuti collaborated on the decorations.