On 16 July 2006, the site "Genoa: le Strade Nuove and the system of the Palazzi dei Rolli" entered UNESCO's World Heritage List of the Convention concerning the Protection of the World Cultural and Natural Heritage.
Forming an organic urban unit, the site is made up of late-Renaissance and Baroque streets and squares lined by over a hundred palaces belonging to the city's noble families.
The grandest residences, each with its own architectural style and individual character, were on official lists (Rolii), and lots were drawn to decide which palace would have the privilege of playing host to visiting state dignitaries.
Often erected on sloping ground, the paiazzi were designed according to the sequence atrium - courtyard - grand staircase - garden and boast richly decorated interiors.
They embody a distinctive social and economic identity and mark the beginning of the era of modern urban architecture in Europe.
Inscription on the World Heritage List confirms the exceptional universal value of a cultural or natural site which deserves protection for the benefit of all humanity.

Link:
Genoa: the Strade Nuove and the System of the Palazzi dei Rolli - Official site (italian)
Italian Ministry for Heritage UNESCO WH Office