The Sanctuary of Madonna delle Grazie in Lanuvio features a church which was rebuilt in 1523, enlarging upon a previous fourteenth century church which can still be made out, and of which the frontispiece of the door and the large Gothic pointed window on the left-hand wall can still be seen. In 1826 it caught fire, and in 1844 it was restored and reopened to the public. The inside finds slender arches and renaissance niches on the right-hand wall. At the back of the church it is possible to see part of the sixteenth-century cloister. The sanctuary is part of the itinerary "Tra Chiese e Santuari" (Amidst Churches and Sanctuaries) which is on the "Strada dei Vini dei Castelli Romani" (Wine Route of the Castelli Romani area).
The Sanctuary, which has played a crucial role in the religious life of Lanuvio, houses the picture of the Madonna delle Grazie, dating back to the 17th century. Each year in May it is carried in a procession through the village streets and is placed in the Collegiata church for a week. At the end of the celebrations the picture is taken back to the Mariano Diocesan sanctuary once again, which is at the southernmost end of the village.