The property as a whole is a particularly representative example of an architectural element of global interest. The portico has been adopted for centuries throughout the world, but it finds its most complete representation in Bologna.
From the 12th century to the present day, Bologna has incessantly proposed porticoes in its buildings, making it become the characteristic element of its urban fabric.
The 12 components, selected among the 62 km of Bolognese porticoes for their representativeness, summarize the whole system and compose a significant set of chronological phases, architectural languages, technical characteristics, urban and social functions. For each of them the original and substantial contribution to the Outstanding Universal Value of the overall series is evident. They were also selected for their high degree of authenticity and integrity and for their relation to each other, as well as for the specific accordance with the criteria of the nomination, for their historical and architectural importance, for the excellent state of conservation they display and for their excellent conditions of accessibility and public usability.