There are more than 900 churches in Rome most Catholic but not all. Of these, there are four major basilicas in the city which fall under the direct supervision of the Pope – Basilica of St. John Lateran (Also the seat of the Bishop of Rome) Basilica di Santa Maria Maggiore, Basilica of Saint Paul, and St. Peter’s. Visiting any one of these many churches will provide you with a crash course in history, architecture and art. Some of my favorites are listed below with a short rationale of why. You could live your entire life in Rome and not visit all of these remarkable structures. If you find yourself walking past a church and the doors are open I encourage you to go inside – you never know what you will discover. Everything from Bernini sculptures to Caravaggio paintings to some interesting relics are housed within these houses of worship.
Crypt of Balbi – you can see in detail the layers of Roman civilization from the earliest days through the Middle Ages and Renaissance. It is like one big layer cake that you get to walk through and actually see and touch the layers. Also very near to the Largo Argentina where Caesar is reputed to have been assassinated.
Santa Cecilia in Trestevere – Somewhat out of the way this church was built over the upper class home of it’s namesake. Be sure to tour the excavations under the church.
San Luigi dei Francesi – Near the Piazza Navona and the Pantheon this church houses three spectacular Caraviaggio paintings, among which include the Calling of Saint Matthew, one of his most powerful works.
Santa Maria sopra Minerva – The only gothic church in Rome. I recommend visiting late in the afternoon when the setting sun is directly in front of the entrance. Before entering, take your picture in front of the famous Bernini baby elephant carrying an obelisk. Among the many notable works of art inside is a wonderful sculpture by Michelangelo, a muscular Christ Bearing the Cross.
via Churches and Crypts.