Bernini's Answer

Two hundred metres further along the same street stands the church that Bernini himself thought of as his best work, and he built it in the very same years his rival was busy with his own.

The Jesuits commissioned him to design Sant'Andrea al Quirinale in 1658, paid for by the Pamphilj family. The facade is a semicircular flight of steps with a porch that steps forward, so the building comes out to meet you, and that is precisely the opposite of the rippling facade of San Carlo, which seems to draw you inward.

Inside he carries that reversal through, because where Borromini laid his oval along its length, Bernini turned his a quarter turn.

The church is free and closes for a couple of hours around midday. Inside, the second part of this stop is waiting, about that oval and about the saint who seems to rise up through the vault.