The church of San Carlo, which is situated near the Church of Saint Joseph was commissioned by the apostolic nuncio of Madrid, Cardinal Cennini. The church was consecrated in 1629 and is dedicated to San Carlo Borromeo. It is unlike the other churches because it is only open to the public at Easter. In the church very important sacred vestments are housed together with a wooden statue representing Christ, dating back to the year 1620.
The drapes of mourning hide decorations and paintings from the 1800s.
At Easter the church is decorated with “veccia”(vicia sativa) plants that have been grown in the dark during Lent so that they are white not green, an old Catholic tradition that refers to the resurrection of Christ (“even in the darkness of death there is life”).