This liveliness dates back to the Middle Ages when Santo Spirito was the site of demonstrations, games and festivals. Many of these celebrations had direct ties to the neighbourhood, such as the Festival of Saint Rocco, the patron saint of the Oltrarno. The feast day of San Rocco falls on August 16 and was traditionally celebrated with a neighbourhood dinner in the piazza. Another regular celebration was the feast day of Saint Martino, patron saint of wool cloths. Today these traditions are remembered in the daily market which fills the piazza every morning, apart from holidays, with fruits and veggies, local products and all manner of merchandise for the house. In the summer months the piazza is transformed in to a theatre of sorts, hosting a variety of concerts and shows.
The piazza is surrounded by 15th century houses, among them the Palazzo Guadagni which was built at the beginning of the 1500s. Its characteristic upper loggia established a fashion and served as a model for a number of other aristocratic palazzi around Florence. The ground floor of this building served as Florence's first public library which opened in 1914. The most significant architecture on the piazza, however, is undoubtedly the basilica, built according to the design of Filippo Brunelleschi and completed at the end of the 15th century. The facade, however, was never finished and today it is a simple, plastered surface. The interior of the church is a treasure chest of important art works including a wooden crucifix by Michelangelo and works by Filippino Lippi, Sansovino, Orcagna, Giuliano da San Gallo.
At the centre of the piazza rises a fountain of pietra serena with a large octagonal basin and two smaller concentric basins raised by a central vertical element of marble.