Since July 2006 it is inscribed in the list of UNESCO World Heritage Site Genoa: the Strade Nuove and the system of the Palazzi dei Rolli.

The move to expand the antique palaces and to build new sumptuous ones was driven by the extraordinary wealth that came into the city through prosperous financing activities towards several European powers.

In particular, the Genoese aristocracy financed the expensive undertakings of the Spanish Crown, such as the mercenary army that Spain kept in Flanders from 1566 to the peace of Westphalia in 1648.

The ruling class of Genoa, mixing nobility of blood with new mercantile wealth, sought to underpin their prestige by the construction of grand city palaces and suburban villas of unusual splendor.

The great, heavy, stone balconies, one above another, and tier over tier: with here and there, one larger than the rest, towering high up—a huge marble platform; the doorless vestibules, massively barred lower windows, immense public staircases, thick marble pillars, strong dungeon-like arches, and dreary, dreaming, echoing vaulted chambers: among which the eye wanders again, and again, and again, as every palace is succeeded by another- the terrace gardens between house and house, with green arches of the vine, and groves of orange-trees, and blushing oleander in full bloom, twenty, thirty, forty feet above the street—the painted halls, mouldering, and blotting, and rotting in the damp corners, and still shining out in beautiful colours and voluptuous designs...