The giant Basilica of St. Paul is Rome’s fourth great patriarchal church, whose origins date from the time of Constantine. It was erected over the tomb of St. Paul and is the second-largest church in Rome after St. Peter’s. The basilica fell victim to fire in 1823 and was subsequently rebuilt—hence the relatively modern look. From the inside, its windows may appear to be stained glass, but they’re actually translucent alabaster that illuminates a forest of single-file columns and mosaic medallions (portraits of the various popes). Its most important treasure however, is a 12th-century marble Easter candelabrum by Vassalletto, the same artist responsible for the remarkable cloisters containing twisted pairs of columns enclosing a rose garden. The baldacchino by Arnolfo di Cambio, dated 1285, miraculously wasn’t damaged in the fire, and now shelters the tomb of St. Paul Apostle.