It is the oldest major basilica in Rome, a city in which religious tourism has an important weight, since it is the Vatican City, seat of the Catholic Church. The architect of this temple was Franceso Borromini and it has an early Christian and Baroque style. You have all the information in: «Rome tourist guide: what to see, itineraries and recommendations«.
You have all the information in: "Rome tourist guide: what to see, itineraries and recommendations".