Some photos, courtesy of a good friend and fellow Baroque enthusiast, Matthew Enquist, of one of my favorite Roman churches, Sant' Agnese in the Piazza Navona, built, I believe, on the site of her martyrdom and containing a relic of her skull, which is about the size of a large baseball, given she was still little more than a girl when she was killed.
Sant' Agnese is one of the most cleverly-designed Baroque churches in the Eternal City, taking what might be a liability--a peculiarly cramped site wider than it is deep, and making it an organic, even essential, aspect of the design. As you study these photos, note the church, while highly ornamented, is actually free of a lot of the Roccoco lettuce that is usually mistaken for Baroque architecture, and also the vivid use of polychromy and colored marble, evidence that classicism has a tradition of striking color as well-established as the Gothic. There is also a clear and well-defined system of iconography at work here, with winged putti playing in the higher, heavenly vaults just as one finds angels in the higher registers of churches from the earliest days of ecclesiastical art, as well as the use of the vegetal Corinthian order as a symbol of Christian triumph (and, also, probably feminine grace) common in numerous Roman shrines.