Quattro Fontane

The renamed Rome Zoo, one of the oldest in Europe, founded in 1911. On the edge of the Borghese Gardens, a short, well-signposted walk from the Gallery. They try hard, but San Diego this isn't. If you are a regular zoo-goer you will be disappointed.

A very ancient church named after a saint who was in 1969 removed from the Roman Catholic calendar of saints for the lack of details of her life. But the church retains the name and is well worth visiting for an excellent 4th-century mosaic and attractive decorations on the facade. Visiting hours are short, but if you arrive close to 11:30, try talking to the attendant if you see him, and he might let you visit for a few minutes. The church is small, so 15 minutes should be long enough to see and absorb everything.

One of the oldest churches in the city. The nave is lined with a mismatched collection of columns taken from ancient Roman buildings. The apse is covered in gold mosaics from the 13th century, arguably the finest mosaics in the city. Impressive mosaics also on the front. According to legend the church was founded in 222, so it would be one of the most ancient churches in the city. Written records mention a church on this place in 337. What is visible today was built in the 12th century, by order of Pope Innocent III. The facade is decorated with mosaics representing the Virgin Mary and ten unidentified figures. Most probably these mosaics are the work of Petro Cavallini who created the mosaics of the lower apse dated 1290 representing scenes from the life of Mary. The mosaics of the upper apse in byzantine style are even older and date from 1140. The columns of the nave originate from the ancient Baths of Caracalla. The facade of Santa Maria in Trastevere is even more impressive at night when it is illuminated.

Church built on the site of three Roman pagan temples, which can be explored underground for a small fee paid at a desk near the church entrance.

Built in 141 AD and dedicated to the Empress Faustina; after her husband emperor Antoninus Pius died in 161 AD the temple was rededicated to the couple.

With Bernini's famous Triton Fountain. Via Veneto starts here too.

This remarkable building served as the site of the Apostolic Chancellery, or offices of the Pope, for centuries, and now houses a Vatican court. Tucked behind the facade is also the Basilica of San Lorenzo in Damaso, an ancient Roman house church rebuilt in the 15th century.

Next door to Santa Croce. A collection of around 3000 pieces, although only a third of these are displayed.

This church was built by the Emperor Constantine (272-337) as a mausoleum for his daughters Constantina and Helena. It was part of a much larger cemetery complex, parts of which can still be seen. The mausoleum was consecrated as a church and dedicated to Constantina when she became a saint in 1254. The building is circular with an inner arcade resting on pairs of granite columns. It retains some marvellous mosaics from the 4th Century.

Pope Nicholas III connected Castel Sant'Angelo to St. Peter's by a covered fortified corridor called the Passetto di Borgo. This proved useful for Pope Clement VII during the Sack of Rome (1527). You can still see much of the Passetto by walking along the Borgo Sant'Angelo, which runs parallel to, and north of, the Via della Conciliazione.

This church is literally right next to the Pantheon. It is one of Rome's only Gothic churches, and well worth looking inside, although its plain square façade makes it look inconspicuous from outside. Excellent stained glass windows.

A 1st-century tomb surrounded by two farmhouses from the Middle Ages, one of which used to be a cheese store. Rather hidden behind a high wall, the tomb is rarely open to the public. You might be lucky on a Sunday: on the third Sunday of every month there is a guided tour at 11:00.

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).

The contours of the ancient stadium, built in the 6th Century B.C., are still visible in what is now a park in the shadow of the Palatine. Circus Maximus was primarily devoted to chariot races and was used for this purpose until around 550 AD. The stadium could seat up to 150,000 people. Originally built of wood, it burnt down twice, on the second occasion starting the great fire when the Emperor Nero was said to fiddle while Rome burned. It was in one of the tunnels here that Caligula met his end. Excavations began in 2009 at the east end of the circus and are likely to go on for some years.

They are posted at entrances to the Vatican City to provide security and protect the Pope. They wear very colourful clothing, similar to the uniforms worn by Renaissance-era soldiers. The Pontifical Swiss Guards is also the smallest and oldest standing army in the world, founded in 1506 by Pope Julius II. The origins of the Swiss guards, however, go back much further as the popes had regularly imported Swiss mercenaries during the 1400s.

Ara Pacis is an altar to peace commissioned by the Roman Senate on 4 July 13 BC to honor the triumphal return from Hispania and Gaul of Augustus. It is universally recognised as a masterpiece. Following discovery of this work under a building in Rome, Mussolini built a protective building for it near the Mausoleum of Augustus, where it was reconstructed. A new building on the same site as Mussolini's was opened in 2006 and has been controversial. The mayor at the time said he would tear down the new structure. The basement of the new building features occasional exhibitions. You can see much of it from outside the building. Paying to go inside adds some background info, but not much more.

An example of urban planning that goes back to Pope Julius II, who, in 1508, envisioned it as a street that would connect all major government buildings. It is around a kilometer long and is in a straight line, an unusual feature for the time. It is lined with some interesting palaces but these days is more known for its antique shops. Via Giulia runs parallel with and one block from the River Tiber.

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.

A strange building, constructed by Reginald Pole, an English cardinal and later Archbishop of Canterbury, allegedly on the spot where he was able to escape from assassins sent by the English King Henry VIII.