Piazza Navona is a compact, lively Baroque square famous for Bernini's Fontana dei Quattro Fiumi and a string of other ornate fountains, so go to admire the sculptures and people-watch rather than to dine on the pricey terrace cafés. It gets very crowded midday and full of street performers and souvenir sellers, so visit early morning or after sunset for better photos and fewer people. Watch your belongings and be wary of aggressive vendors or small scams; most places take cards but check for a "coperto" cover charge before you sit. The cobblestones and tight sidewalks can be awkward with strollers or wheelchairs, and it’s an easy walk from the Pantheon and Campo de’ Fiori if you want to combine sights.