Calci's Parish Church of Santi Giovanni Avangelista ed Ermolao dates back to the 11th century, when building began at the order of archbishop Daiberto and was completed by Countess Matilde of Tuscany. Its facade is in the Pisan Romanesque style, divided by two rows of blind arches with geometrical properties typical of Pisan architecture.
A sturdy bell tower, a still-incomplete construction of brick and stone, rises on the left. High up on the same side of the church is fixed an ancient sculpture of a head, perhaps that of Jupiter Ammon. The interior is divided into three naves, separated by granite columns which are topped with Ionic and Corinthian capitals.
The main altar, made from Carrara marble, is highly interesting, but so is the 18th-century oil-painted altarpiece that depicts the Madonna and Child between the saints Ermolao and Francesco, and the baptismal font with four basins, sculpted from a single block of marble and decorated with reliefs by the school of Biduino in the 12th century.