The Strade Nuove -- the 'New Streets' -- were constructed during the apex of Genoese financial and maritime power. Via Giuseppe Garibaldi, originally called Strada Nuova, was laid out between 1558 and 1583. Via Balbi followed from 1602 to 1620, and Via Cairoli, the Strada Nuovissima, was completed between 1778 and 1786. These were not ordinary streets. They were purpose-built corridors of aristocratic display, lined with Renaissance and Baroque palaces designed to impress foreign visitors with Genoa's wealth and taste. The architecture adapted to Genoa's steep, cramped topography with remarkable ingenuity -- palaces incorporated dramatic staircases, terraced gardens, and light wells that transformed narrow hillside lots into spaces of surprising grandeur. Peter Paul Rubens was so taken with the palaces that he published a book of their architectural drawings in 1622.

The Rolli system divided palaces into three categories based on size, beauty, and importance. Only three palaces qualified for the highest tier -- suitable for popes, emperors, and kings: Palazzo Doria Spinola, Palazzo Grimaldi Doria Tursi, and Palazzo Lercari Parodi, the latter two both on today's Via Garibaldi. When a state visit was announced, a lottery determined which palace would host the guest, with the selection matched to the visitor's rank. Cardinals and viceroys drew from one list, ambassadors and governors from another. Five official lists survive, spanning from 1576 to 1664, cataloguing between 52 and 150 palaces at various dates -- 163 different palaces appeared at least once. The system expressed a core principle of the Republic: no single family should monopolize power or prestige.

Forty-two of the original Rolli palaces received UNESCO World Heritage status in 2006, selected from the 163 that appeared on the historic lists. Today, three of the most important -- Palazzo Rosso, Palazzo Bianco, and Palazzo Doria Tursi -- form the Strada Nuova Museums on Via Garibaldi, housing art collections that include works by Caravaggio, Van Dyck, and Rubens. Others serve as government offices, university buildings, and private residences. Since 2009, the city has organized Rolli Days twice yearly, opening both public and private Rolli palaces for free guided tours. Art students, architects, and professional guides lead visitors through halls that once hosted the diplomacy of a maritime empire. The number of buildings participating has grown steadily, expanding to include churches, suburban villas, and university buildings beyond the original Rolli system.

The UNESCO designation recognized something more than fine architecture. The Strade Nuove and the Rolli system together document a unique model of governance and urban planning. Where monarchies centralized power in a single court, Genoa distributed it across a network of private residences elevated to public purpose. The palaces' extraordinary variety -- each adapting Renaissance and Baroque conventions to different sites, different families, different visions of magnificence -- reflected an oligarchic republic in which competition among peers drove both artistic patronage and civic identity. Walking Via Garibaldi today, the facades still compete with one another for attention: frescoed interiors visible through open doorways, courtyards filled with statuary, gardens climbing the hillside behind. Genoa's 'New Streets' were built to make an impression on foreign visitors. Five centuries later, they still do.