City walls
The construction of the first lot near the Duomo, in tuff stone, dates back to 1154. The first strip of gray limestone, called San Giuliano marble, to the north of the city is erected from 1154 to 1161. The later bands of the northern part and the whole the southern part are built in various phases, from 1161 to 1346 (with Asciano's rosy gray stone). There are further interventions during the fifteenth century and later between the late nineteenth and early twentieth centuries with demolitions to the section of the walkway at high altitude from Piazza delle Gondole to Torre del Barbagianni is accessible to the disabled only with support because there are steps.