The Site: This riotously baroque 17th-century church is most famous for Bernini's lavish Cornaro Chapel.
The Secret: Bernini transformed the Cornaro Chapel in into a theater stage. Members of the Cornaro family, which bankrolled the chapel, peek out from ingenious high- and low-relief "box seats" on the walls (accompanied by Bernini, last guy on the left), and what they're watching is infamously scandalous. St. Teresa of Avila—draped in a flowing mass of folded robes, head thrown back, mouth half-open in a moan—writhes beneath a smiling, spear-wielding angel. It's meant to portray a moment of religious ecstasy, but few who see it can help wonder whether Bernini was inspired by something more earthly.