Santa Maria di Montesanto
Santa Maria dei Miracoli
In this picture the ancient obelesque at the center is framed by the two churches as the south end of the Piazza del Popolo. The churches were designed by architect Carlo Rainaldi, a peer of Bernini and Borromini. To provide a focal point for the piazza, the churches has to look symetrical, but the site on the left was narrower. So Rainaldi gave Santa Maria dei Miracoli, on the right, a circular and Santa Maria in Montesanto an oval one, cleverly squeezing it into the narrower site, while the sides of the supporting drums that face the piazza are identical.