Basilica of Saint Lawrence Outside the Walls

More modern than most Roman churches: it was not started until 1873. This is Rome’s Episcopalian church. Some very interesting artwork, particularly the mosaics by Edward Burne-Jones of the Pre-Raphaelite school.

Located a short walk west of the Colosseum, this well-preserved monumental arch was erected (soon after 315) to commemorate the victory of Constantine, the first Christian emperor, over his rival Maxentius at the Battle of the Milvian Bridge in 312. In general design, the Arch of Constantine imitates the century-earlier Arch of Septimius Severus (nearby in the Forum). The three arches are decorated utilizing mainly materials plundered from other imperial monuments by Trajan, Hadrian and Marcus Aurelius. The quality of its sculptural decoration, however, betrays the slow degradation that Classical Roman sculpture had experienced in the 3rd century AD.

Built in the 17th century to a design based on an architectural sketch by Michelangelo. Highlights include the ancient Colossus of Constantine statue (the Colosseum was probably named for another giant statue, the Colossus of Nero which stood near the Flavian Amphitheatre as the Colosseum was originally known), The Dying Gaul, a magnificent marble sculpture that copies a bronze Greek original of the 3rd century BC and the Capitoline Venus. It also contains the remarkable original gilt bronze equestrian statue of emperor Marcus Aurelius (the one in the piazza is a replica).

Home of the Abbot Primate of the Benedictine Confederation and Benedictine monks studying in Rome. Visit the monastic produce shop and listen to the best Gregorian chant in Rome during Vespers (19:15 each evening).

A medieval church dating from the 6th century and home to the Bocca della Verità (Mouth of Truth). The Bocca della Verità at the entrance to the church is thought to be a 1st-century manhole cover. It is believed that if you put your hand in the mouth and tell a lie, the hand will be bitten off. Queues for the privilege of risking this can get rather long. Don't ignore the church, which is a gem, and has a separate entrance. Its mosaic floor in the Cosmatesque style is more rustic and less intricate than some others (Santa Maria in Trastevere, for example), but its simplicity gives it a solidity not found in the more ornate styles. S.M. in Cosmedin has a fine medieval choir enclosure and the tallest medieval belfry in Rome.

This museum is built on top of the excavation site of the Balbi Crypt, a building from the first century A.D. which underwent considerable modifications in the following centuries. Through the building's history, the museum gives us glimpses of what Roman life across the ages was like. Free visits of the ruins are possible. The Essedra ruins are only accessible on Saturdays and Sundays, at 10:45, 11:45, 12:45, 14:45 and 15:45.

Between the Pantheon and Via del Corso. A stunning example of Baroque art. The ceiling frescoes are especially fine, including a trompe l'oeil dome by the master Andrea Pozzo.

According to the legendary passio, two brothers, John and Paul, who were officials at the imperial court, suffered martyrdom in 362 in their home on the Caelian hill, during the reign of emperor Flavius Claudius Julianus. This basilica dedicated to these two Roman officers was erected starting from 398 and was used first as a domus ecclesiae by the Christian community.

The temple of the Emperor Hadrian was consecrated in 145 AD by Emperor Antoninus Pius. The remains of the antique temple were incorporated into a new building that served as the Papal Customs House. It was finished around 1690 and today accommodates the Stock Exchange (Borsa).

This palace of the 16th century was erected by the famous Medici family. It was the residence of Cardinals Giovanni and Giuliano Medici, later Pope Leo X. and Clement VII. Catherine de Medici, Pope Clement VII's niece lived here until her marriage in 1553 with Prince Henry, the son of King Francis I of France. The palace is named after Madama Margerita of Austria, the illegitimate daughter of Emperor Charles V. Since 1871 it has been the seat of the Italian Senate.

If it is sunny, you'll catch a few young people and older gentlemen sitting at the base of a statue in the middle of the open space. The statue is a brooding, hooded Giordano Bruno—an excommunicated Dominican monk and one of the earliest cosmologists who held the idea of an infinite universe. He was burnt at the stake for heresy on this spot on 17 February 1600. The piazza is used as a marketplace during the day, and party central for college students and tourists at night. When the sky gets dark and the street lamps go on, the Campo de' Fiori fills with people and lovers wander arm in arm in the crowd. Over the buzzing of conversation and the occasional burst of laughter you may hear a young vocalist belt out O Sole Mio at the top of his lungs as change plunks into his accordion case.

More of an enormous traffic circle than a piazza, but a good central location. The centerpiece is the enormous Vittorio Emanuele Monument (aka the Wedding Cake or the Typewriter) with the Capitoline hill next door. Mussolini used to harangue Romans from the first floor balcony of Palazzo Venezia (see under Museums), to the west of the square.