The main facade of this eccentric Baroque church, probably Borromini's best, is on the stately courtyard of an austere building that once housed Rome's university. Sant'Ivo has what must surely be one of the most delightful domes in all of Rome—a golden spiral said to have been inspired by a bee's stinger. The bee symbol is a reminder that Borromini built the church on commission from the Barberini pope Urban VIII (a swarm of bees figure on the Barberini family crest). The interior, open only for three hours on Sunday, is worth a look, especially if you share Borromini's taste for complex mathematical architectural idiosyncrasies. "I didn't take up architecture solely to be a copyist," Borromini once said. Sant'Ivo is certainly the proof.