Located in Croglio, in the hamlet of Castelrotto, the Church of St Nazaro, already mentioned in 1301, was built in its present form in the mid 17th century and has a majestic façade. The bell tower dates back to 1677.
Inside, the nave follows the rhythm of the façade. On the imposing Baroque high altar with 18th-century stucco and marble, there is a statue of the Assumption by Antonio Camuzzi of Montagnola (1690). The two side chapels contain statues of the Madonna from the 18th century. In the baptistery, decorated in stucco by Giovanni Maria Per (1718), a fresco from the same year with the Baptism of Jesus in the Jordan by Bartolomeo Rusca of Arosio.