The Fontana Maggiore was built between 1278 and 1280 by Nicola and Giovanni Pisano, to celebrate the completion of the new aqueduct. The project is due to frà Bevignate, while the hydraulic part was carried out by Boninsegna da Venezia.
The Fountain has been receiving water from Mount Pacciano for more than 700 years.
It is composed of two concentric overlapping basins, decorated with 50 bas-reliefs and 24 statues. The lower basin bears bas-relief: scenes from the agricultural tradition, the months of the year with the signs of the zodiac, the Liberal Arts, the Bible and the history of Rome. The upper basin is composed of twenty-four slabs separated by statues representing allegorical, sacred and historical figures.
The basins are surmounted by a bronze cup crowned by a group of three nymphs, representing the three theological virtues (Faith, Hope, Charity).