Church of San Luigi dei Francesi

If you're a fan of Caravaggio, you'll want to visit the San Luigi dei Francesi. Inside this Navona church are three of the baroque artist's works, including the Calling of St. Matthew (one of his most famous works), Matthew and the Angel, and Matthew's Martyrdom. There's no cost of admission, but the church does close for lunch each day, as well as all of Wednesday. You'll find this church in the Navona neighborhood and off the Barberini metro stop (though be prepared for an about 15-minute walk).