Located in Piazza del Popolo, looking at Via del Corso to the right, it is one of the twin sisters along with Santa Maria in Montesanto. Drawn by architect Carlo Rainaldi in 1611, it was completed by Bernini with the collaboration of Carlo Fontana by initiative of monsignor Girolamo Gastaldi.
With a central plan it is preceded by a pronaos decorated by statues surmounted by domes. The inside holds two chapels per side and a rich high altar with a picture of the Vergine supported by four angels, a work by Antonio Raggi.
Splendid are the momuments of Cardinal Girolamo Gastaldi and his brother, Marquis Marchese Benedetto.
The dome is rounded, differently from the one of the twin church of Santa Maria di Montesanto that is oval, even though they look the same.