The Piazza della Cisterna is the most beautiful and famous piazza in all of San Gimignano. It is enclosed by a wall of nobility houses and medieval towers. It marks the junction between the two most important roads: the Francigena and the road leading from Pisa to Siena. It was the heart of San Gimignano, forming, along with the Piazza Duomo, the cornerstone of the medieval city. While Piazza Duomo was the religious and political centre, the Piazza della Cisterna was the place dedicated to popular culture, with a marketplace and a site for holding public performances, festivals, and tournaments.
Its appearance is attributable to the 13th-century layout undertaken in accordance with the rules set by the Ghibelline comune. It is shaped like an inverted triangle and takes advantage of the natural slope of the land. It is completely paved in brick and connects to the Piazza del Duomo with an open passageway.
Its name comes from a water cistern found at the centre of the site, where an octagonal travertine well forms a pivot point in the piazza. It offers a view out through the straight passageway of Arco dei Becci, one of the gates in the ancient medieval wall.
Next to the gate are the charming Torri dei Becci and Torri dei Cugnanesi. Nearer the well are very important buildings: the Palazzo Razzi, with its splendid two-light mullioned windows; Casa Salvestrini, which at one time was a hospital and is now a hotel; and Palazzo Tortoli, which is next to the severed tower that belonged to the Capitano del Popolo (it was cut down during struggles between rival families).
To the north are the Palazzo dei Cortesi and the charming Torre del Diavolo, with the unusual name and its unsettling connection to a mysterious legend.
After the Case dei Cattani on the same side, the passageway leads to the Piazza del Duomo. The opposite side of the piazza consists of different palazzos with façades constructed with different coloured materials. They all belonged to the nobility. To the west, on the side that borders the Loggia del Comune, are the Torri Gemelle of the Ardinghelli and the tower of the Palazzo Pellari.
From the piazza one enters the narrow Vicolo dell'Oro, an alley so named because there were goldsmiths and hammerers (artisans who created the very thin gold leaf used to cover the wood bases for polittici, the frescoed tables with the images of the saints, that decorated the church altars).