12 Best Sights in Ancient Rome, Rome

One of the most impressive archaeological sites in Rome, San Clemente is a historical triple-decker. A 12th-century church was built on top of a 4th-century church, which had been built over a 2nd-century pagan temple to the god Mithras and 1st-century Roman apartments. The layers were uncovered in 1857, when a curious prior, Friar Joseph Mullooly, started excavations beneath the present basilica. Today, you can descend to explore all three.

The upper church (at street level) is a gem in its own right. In the apse, a glittering 12th-century mosaic shows Jesus on a cross that turns into a living tree. Green acanthus leaves swirl and teem with small scenes of everyday life. Early Christian symbols, including doves, vines, and fish, decorate the 4th-century marble choir screens. In the left nave, the Castiglioni chapel holds frescoes painted around 1400 by the Florentine artist Masolino da Panicale (1383–1440), a key figure in the introduction of realism and one-point perspective into Renaissance painting. Note the large Crucifixion and scenes from the lives of saints Catherine, Ambrose, and Christopher, plus the Annunciation (over the entrance).

To the right of the sacristy (and bookshop), descend the stairs to the 4th-century church, used until 1084, when it was damaged beyond repair during a siege of the area by the Norman prince Robert Guiscard. Still intact are some vibrant 11th-century frescoes depicting stories from the life of St. Clement. Don't miss the last fresco on the left, in what used to be the central nave. It includes a particularly colorful quote—including "Go on, you sons of harlots, pull!"—that's not only unusual for a religious painting, but also one of the earliest examples of written vernacular Italian.

Descend an additional set of stairs to the Mithraeum, a shrine dedicated to the god Mithras. His cult spread from Persia and gained a foothold in Rome during the 2nd and 3rd centuries AD. Mithras was believed to have been born in a cave and was thus worshipped in cavernous, underground chambers, where initiates into the all-male cult would share a meal while reclining on stone couches, some visible here along with the altar block. Most such pagan shrines in Rome were destroyed by Christians, who often built churches over their remains, as happened here.

Perched up the incline of the Clivio di Scauro—a magical time-machine of a street, where the dial seems to be stuck somewhere in the 13th century—Santi Giovanni e Paolo is an image that would tempt most landscape painters. Marked by one of Rome's finest Romanesque bell towers, it looms over a picturesque piazza. Underneath, however, are other treasures, whose excavations can be seen in the Case Romane del Celio museum.

A basilica erected on the spot was, like San Clemente, destroyed in 1084 by attacking Normans. Its half-buried columns, near the current church entrance, are visible through misty glass. The current church's origins date to the start of the 12th century, but most of the interior dates to the 17th century and later. The lovely, incongruous chandeliers are hand-me-downs from New York's Waldorf-Astoria hotel, a gift arranged by the late Cardinal Francis Spellman of New York, whose titular church this was. Spellman also initiated the excavations here in 1949.

Michelangelo's Moses, carved in the early 16th century for the never-completed tomb of Pope Julius II, has put this church on the map. The tomb was to include dozens of statues and stand nearly 40 feet tall when installed in St. Peter's Basilica. But only three statues—Moses and the two that flank it here, Leah and Rachel—had been completed when Julius died. Julius's successor as pope, from the rival Medici family, had other plans for Michelangelo, and the tomb was abandoned unfinished.

The fierce power of this remarkable sculpture dominates its setting. People say that you can see the sculptor's profile in the lock of Moses's beard right under his lip and that the pope's profile can also be seen. As for the rest of the church, St. Peter takes second billing to Moses. The reputed sets of chains (vincoli) that bound St. Peter during his imprisonment by the Romans in both Jerusalem and Rome are in a bronze and crystal urn under the main altar. Other treasures include a 7th-century mosaic of St. Sebastian, in front of the second altar to the left of the main altar, and, by the door, the tomb of the Pollaiuolo brothers, two 15th-century Florentine artists.

Despite its florid 18th-century facade, Santa Maria Maggiore is one of the city's oldest churches, built around 440 by Pope Sixtus III. One of Rome's four great pilgrimage churches, it's also the city center's best example of an early Christian basilica—one of the immense, hall-like structures derived from ancient Roman civic buildings and divided into thirds by two great rows of columns marching up the nave. The other three major basilicas in Rome (San Giovanni in Laterano, St. Peter's, and St. Paul Outside the Walls) have largely been rebuilt. Paradoxically, the major reason why this church is such a striking example of early Christian design is that the same man who built the undulating exteriors circa 1740, Ferdinando Fuga, also conscientiously restored the interior, throwing out later additions and, crucially, replacing a number of the great columns.

Precious 5th-century mosaics high on the nave walls and on the triumphal arch in front of the main altar bear splendid testimony to the basilica's venerable age. Those along the nave show 36 scenes from the Old Testament (unfortunately, tough to see clearly without binoculars), and those on the arch illustrate the Annunciation and the Youth of Christ. The resplendent carved-wood ceiling dates from the early 16th century; it's supposed to have been gilded with the first gold brought from the New World. The inlaid marble pavement (called cosmatesque, after the family of master artisans who developed the technique) in the central nave is even older, dating from the 12th century.

The Cappella Sistina (Sistine Chapel), in the right-hand transept, was created by architect Domenico Fontana for Pope Sixtus V in 1585. Elaborately decorated with precious marbles "liberated" from the monuments of ancient Rome, the chapel includes a lower-level museum in which some 13th-century sculptures by Arnolfo da Cambio are all that's left of what was the once richly endowed chapel of the presepio (Christmas crèche), looted during the Sack of Rome in 1527.

Directly opposite, on the church's other side, stands the Cappella Paolina (Pauline Chapel), a rich Baroque setting for the tombs of the Borghese popes Paul V—who commissioned the chapel in 1611 with the declared intention of outdoing Sixtus's chapel across the nave—and Clement VIII. The Cappella Sforza (Sforza Chapel) next door was designed by Michelangelo and completed by Della Porta. Just right of the altar, next to his father, lies Gian Lorenzo Bernini; his monument is an engraved slab, as humble as the tombs of his patrons are grand. Above the loggia, the outside mosaic of Christ raising his hand in blessing is one of Rome's most beautiful sights, especially when lighted at night.

Home to one of the most striking early Christian mosaics, this church was adapted in the 6th century from two ancient buildings: the library in Vespasian's Forum of Peace and a hall of the Temple of Romulus (dedicated to the son of Maxentius, who had been named for Rome's founder). In the apse is the famous AD 530 mosaic of Christ in Glory. It reveals how popes at the time strove to recreate the splendor of imperial audience halls into Christian churches: Christ wears a gold, Roman-style toga, and his pose recalls that of an emperor addressing his subjects. He floats on a blue sky streaked with a flaming sunset—a miracle of tesserae mosaic work. To his side are the figures of Saint Peter and Saint Paul, who represent Cosmas and Damian (patron saints of doctors), two Syrian benefactors whose charity was such that they were branded Christians and condemned to death. Beneath this awe-inspiring work is an enchanting mosaic frieze of holy lambs.

Perched atop 124 steps, on the north slope of the Capitoline Hill, Santa Maria in Aracoeli occupies the site of the temple of Juno Moneta (Admonishing Juno), which also housed the Roman mint. According to legend, it was here that the Sibyl, a prophetess, predicted to Augustus the coming of a Redeemer. Augustus responded by erecting an altar, the Ara Coeli (Altar of Heaven). This was eventually replaced by a Benedictine monastery and then by a church, which was passed in 1250 to the Franciscans, who restored and enlarged it in Romanesque-Gothic style.

Today, the Aracoeli is best known for the Santo Bambino, a much-revered olivewood figure of the Christ Child (a copy of the 15th-century original, which was stolen in 1994). At Christmas, everyone pays homage to the "Bambinello" as children recite poems from a miniature pulpit. In true Roman style, the church interior is a historical hodgepodge, with classical columns and large marble fragments from pagan buildings, as well as a 13th-century cosmatesque pavement. The richly gilded Renaissance ceiling commemorates the naval victory at Lepanto in 1571 over the Turks. The first chapel on the right is noteworthy for Pinturicchio's frescoes of St. Bernardino of Siena (1486).

Apart from Ravenna, Rome has some of Italy's most opulent mosaics, and this church has the earliest example. Commissioned during the papacy of Innocent I, its early 5th-century apse mosaic, depicting Christ teaching the apostles, sits above a Baroque altarpiece surrounded by a bevy of florid 18th-century paintings. The mosaic is remarkable for its iconography; at the center sits Christ Enthroned, shown as an emperor or as a philosopher holding court, surrounded by his apostles. Each apostle faces the spectator, literally rubbing shoulders with his companion (unlike later hieratic styles in which each figure is isolated) and bears an individualized expression. Above these figures and a landscape symbolizing Heavenly Jerusalem float the signs of the four evangelists in a blue sky flecked with the orange of sunset, made from thousands of tesserae (mosaic tiles).

To either side of Christ, saints Praxedes and Pudentiana hold wreaths over the heads of saints Peter and Paul. These two women were actually daughters of the Roman senator Pudens (probably the one mentioned in 2 Timothy 4:21), whose family befriended both apostles. During the persecutions of Nero, both sisters collected the blood of many martyrs before suffering their fate. Pudentiana transformed her house into a church, but her namesake church was constructed over a 2nd-century bathhouse. Beyond the sheer beauty of the mosaic work, the size, rich detail, and number of figures make this both the last gasp of ancient Roman art and one of the first major works of Early Christian art.

Situated on one of those evocative cul-de-sacs in Rome where history seems to be holding its breath, this quiet citadel has resisted the tides of time and traffic. The church—which is both strongly imbued with the sanctity of the Romanesque era and marvelously redolent of the Middle Ages—dates from the 4th century and honors the Four Crowned Saints: the four brothers Severus, Severianus, Carpophorus, and Victorinus, all Roman officials who were whipped to death for their faith by Emperor Diocletian (284–305).

After its 9th-century reconstruction, the church was twice as large as it is now; the abbey was partially destroyed during the Normans' sack of Rome in 1084 but reconstructed about 30 years later. This explains the inordinate size of the apse in relation to the small nave. Don't miss the cloister, with its well-tended gardens and 12th-century fountain. The entrance is the door in the left nave; ring the bell if it's not open.

There's another medieval gem hidden away off the courtyard at the church entrance: the Chapel of San Silvestro. The chapel has remained, for the most part, as it was when consecrated in 1246. Some of the best-preserved medieval frescoes in Rome decorate the walls, telling the story of the Christian emperor Constantine's recovery from leprosy thanks to Pope Sylvester I. Note, too, the delightful Last Judgment fresco above the door, in which the angel on the left neatly rolls up sky and stars like a backdrop, signaling the end of the world.

Set amid the greenery of the Celian Hill, this church wears its Baroque facade proudly. Dedicated to St. Gregory the Great (who served as pope 590–604), it was built about 750 by Pope Gregory II to commemorate his predecessor and namesake. The church of San Gregorio itself has the appearance of a typical Baroque structure, the result of remodeling in the 17th and 18th centuries. But you can still see what's said to be the stone slab on which the pious St. Gregory the Great slept; it's in the far right-hand chapel.

Outside are three chapels. The right chapel is dedicated to Gregory's mother, Saint Sylvia, and contains a Guido Reni fresco of the Concert of Angels. The chapel in the center, dedicated to Saint Andrew, contains two monumental frescoes showing scenes from the saint's life. They were painted at the beginning of the 17th century by Domenichino (The Flagellation of St. Andrew) and Guido Reni (The Execution of St. Andrew). It's a striking juxtaposition of the sturdy, if sometimes stiff, classicism of Domenichino with the more flamboyant and heroic Baroque manner of Guido Reni.

This church, a 10th-century edifice with a Renaissance facade, is dedicated to the patron saint of motorists. On her feast day, March 9, cars and taxis crowd the Via dei Fori Imperali below for a special blessing—a cardinal and carabinieri (Italian military) are on hand and a special siren starts off the ceremony. The incomparable setting continues to be a favorite for weddings.

This small, inconspicuous, 9th-century church is known above all for the exquisite Cappella di San Zenone, just to the left of the entrance. It gleams with vivid mosaics that reflect their Byzantine inspiration. Though much less classical and naturalistic than the earlier mosaics of Santa Pudenziana, they are no less splendid, and the composition of four angels hovering on the sky-blue vault is one of the masterstrokes of Byzantine art. Note the square halo over the head of Theodora, mother of St. Paschal I, the pope who built this church. It indicates that she was still alive when she was depicted by the artist.

The chapel also contains one curious relic: a miniature pillar, supposedly part of the column at which Christ was flogged during the Passion. It was brought to Rome in the 13th century. Over the main altar, the magnificent mosaics on the arch and apse are also in rigid Byzantine style. In them, Pope Paschal I wears the square halo of the living and holds a model of his church.

This 5th-century church is thought to have been inspired by the design of the Church of the Holy Sepulchre in Jerusalem. Its unusual round plan and timbered ceiling set it apart from most other Roman churches. So do the frescoes, which lovingly depict 34 of the goriest martyrdoms in Catholicism—a catalog, above the names of different emperors, of every type of violent death conceivable. (You've been warned: these are not for the fainthearted.)