The Sanctuary, formerly the Church of Santa Maria delle Grazie, was built on the site of a previous church, seat of the Confraternity of St. Michael.
Today's building, built between 1756 and 1758 on behalf of the Confraternity of St. Michael the Archangel, is the only church built by Count Francesco Ottavio Magnocavalli completed according to the latter's original project and reflects clear neo-Palladian influences that go beyond the late Baroque style.
The façade is characterised by exposed brickwork, but the presence of pound-holes and rustic capitals suggest a primitive project of stuccoing, plastering and painting. Of great elegance - also in its simplicity - the façade is almost straight, slightly jutting out in the central part and bipartite in two superimposed orders, separated by an entablature. Flat pilasters on a high base rhythm the surface for the whole height, while six columns, leaning against the wall (three on each side), enliven the façade with their chiaroscuro. The trabeation of the second order ends with a triangular tympanum, limited to the central area.
The Sanctuary has a single nave divided into two bays by an intermediate span and sees the presence of four chapels placed at the same time as the four side altars equally divided on both sides of the building. The vaults are built on an elliptical base while the apsidal basin is divided into three segments.
In the apsidal area, in the central area is preserved the late medieval icon from the destroyed parish church of Santa Maria di Piazza. It is a fresco of the Madonna and Child inserted in a rectangular canvas representing "San Michele e il drago" and attributed to Vitalino Grassi. St. Michael sitting on a cloud beats the dragon with one foot and holds him in chains, while an angel faces him with a sword. With his left hand St. Michael holds the
small painting on tuff, while six little angels fly high and two of them seem to help the Saint to support the painting. The fresco was probably brought to the ancient church of Santa Maria delle Grazie between 1536 and 1575 and came from the church of Santa Maria di Piazza.
In the apse and in the presbytery there are four paintings by Giuseppe Costanzi "Visitazione", "Annunciazione", "Natività di Maria" and "Assunzione" and the oil on canvas "Santa Francesca Romana" by Guglielmo Caccia.
Of particular interest is the painting "The Guardian Angel" made in 1760 by Vittorio Amedeo Grassi on commission of Pietro Antonio Caroelli and Pietro Antonio Bertarelli.
The altar dedicated to St. Teresa is evocative and presents a painting by the painter Luca Mancini. The church is equipped with a beautiful small organ, built in 1821 and due to the organ builders from Bergamo Sgrassi, the same who were responsible for the organ of St. Francis later transformed by the Mascioni family in the twentieth century, as we have seen in another chapter. The keyboard has 50 boxwood keys, the pedalboard is a lectern, one octave effective; 18 registers. The sound, clear and brilliant, is especially suited to the Italian repertoire of the eighteenth century.