You wouldn't dream of visiting Rome without visiting St. Peter's Basilica, the Pantheon, and maybe even S. Maria Maggiore. Here are my top ten lesser known churches you may want to add to your "must-see" list:
10. Santa Maria Sopra Minerva (Basilica of St. Mary over Minerva) - the only Gothic church in Rome.
9. Santa Maria in Cosmedin - standing on the original site of an ancient Roman temple, the complex was transformed into a church in 772-95. The porch houses the Bocca della Verita, the "Mouth of Truth" (a marble Roman artifact; its name derives from a medieval legend that if a liar placed his hand in its mouth, it would be bitten off. (Location: Pz. della Bocca della Verita/18, near the Roman Forum)
8. Santa Maria degil Angeli (St. Maria of the Angels Basilica) - designed by Michelangelo inside a structure of ancient baths; it also serves as a personal monument to Pope Pius IV, whose tomb is in the apse. (Location: Pz. della Repubbica)
7. Santissimi Apostoli (Holy Apostles Basilica) - this church dates back to the 6th century; Michelangelo was buried here after his death, but his body was later stolen and carried off to Florence by his nephew, where he was buried in Santa Croce. (Location: Pz. SS. Apostoli, near Piazza Venezia)
6. Santa Maria in Trastevere - dating from the 4th century, this church is believed to be the first place of
Christian worship in Rome. A column next to the alter marks the spot where, according to legend, a stream of pure oil flowed from the earth on the day Christ was born, signifying the coming of the grace of God. (Location: Pz. S. Maria in Trastevere)
5. San Pietro in Vincoli (St. Peter in Chains Basilica) - first built in mid-5th century to house the relics of the chains that bound Saint Peter while imprisoned in Jerusalem. According to legend, Empress Eudoxia (wife of Emperor Valentinian III) gave Pope Leo I the chains as a gift. He compared them to the chains of St. Peter's first imprisonment in the Mamertine Prison in Rome, and the two chains miraculously fused together. The chains are kept under the main alter in the basilica. The church also hosts Michelangelo's statue Moses. (Location: Pz. San Pietro in Vincoli, near the Colosseum)
4. Basilica di San Paolo fuori le Mura (Basilica of Saint Paul Outside the Walls) - originally founded by Emporer Constantine in the 4th century, the Basilica of Saint Paul is the burial place of Saint Paul the Apostle. (Location: Via Ostiense/186, outside of city center near Metro Basilica San Paolo)
3. Santa Prassede - dedicated to St. Prassede (or Praxedes), daughter of Pudens, in whose house St. Peter reportedly stayed while in Rome. The small chapel of St. Zeno, off the right aisle and through a doorway flanked by ionic columns, was built as a mausoleum. In a niche on the right side of the chapel is a large piece of a black granite column, said to be the Column of Flagellation (the pillar to which Christ was tied as he was scourged before the crucifixion). (Location: Via de Santa Prassede/9, near St. Maria Maggiore)
2. San Giovanni in Laterano (Basilica of St. John Lateran) - dedicated to John the Baptist, this basilica was built by Constantine the Great in the 4th century. The Alter of the Holy Sacrament contains a cedar table that is believed to be the one used by Christ at the Last Supper. (Location: Pz. San Giovanni in Laterano/4, near Metro San Giovanni)
1. Santa Croce in Gerusalemme (Holy Cross in Jerusalem) - the 4th century church is located on a Roman imperial estate and houses an extraordinary collection of relics from the Holy Land. At the top of a wide staircase is the Chapel of the Holy Relics where enshrined are: the bone of an index finger (top shelf, left), believed to be the finger of St. Thomas; a container (top shelf, middle) containing small pieces of the Scouring Pillar (to which Christ was tied as he was beaten) and the Holy Sepulchre (Christ's tomb); two thorns (top shelf, right) from the Crown of Thorns; three fragments from the True Cross (middle shelf); one nail used in the Crucifixion (bottom shelf, left); and the Title of the Cross (bottom shelf, right) inscribed with "Nazarene" written in Hebrew, Latin and Greek. (Location: Piazza di Santa Croce in Gerusalemme, near San Giovanni in Laterano Basilica)