Situated near Piazza Navona, the clock tower was built by Borromini between 1647 and 1648 to embellish a corner of the Convent of the Oratorians of San Filippo Neri. The concave façade and rear and the convex sides are typical of Borromini. The mosaic of the Virgin (“Madonna della Vallicella”) under the great central clock was instead created by Pietro da Cortona, while the small tabernacle of the Madonna surrounded by angels, on the corner of the building, is in Bernini’s typical style. The tower rises above a slightly protruding four-storey building with windows, crowned by two inscribed pillars with 24-pointed bronze heraldic stars.