This fresco by Fra Angelico is one of my favorite depictions of the Annunciation. It is in a cell in the monastery of San Marco in Florence, Italy. I envy the monk that had this “come una volta.”

The figure you see standing in the background, watching the Annunciation take place is St. Peter Martyr, a Dominican saint. Fra Angelico includes this saint in a lot of his paintings at the monastery of San Marco.