There are still plenty of reminders of Rome's days as the centre of a massive ancient empire stretching from Iran to Britain. All over the city you'll come across fragments of aqueducts, temples, walls or streets, but the most well-preserved and important ancient sites all lie fairly close to each other, behind the massive 19th-century monument to King Victor Emanuel on Piazza Venezia.
The Roman Forum was the political, business and social heart of the ancient city, where people came to shop, pray or merely pass the time of day. Today you can see the triple vault of the basilica of Maxentius and Constantine, that Renaissance architects including Michelangelo and Bramante, studied as a basis for their own work. Basilicas contained shops and courtrooms and were important commercial and business centres in ancient Rome. There were also a great many temples in the area, the round one was the temple of Vesta, with the remains of the house of the Vestal Virgins next door. The arch nearest Piazza Venezia was built to honour Septimus Severus, while the one at the other end of the Forum commemorates and illustrates Titus' sack of Jerusalem in 70 AD.
The hill above the Forum (the Palatine) was where the emperors had their palaces. Today it's a peaceful, green spot with good views over the Forum. Underneath the pretty Renaissance gardens, built for Cardinal Alessandro Farnese in the mid-16th century, is a long tunnel constructed by Nero in the first century. Its purpose is unclear: it may have been a hot-weather promenade or it may have linked the Palatine to the emperor's palace on Monte Oppio; at its far end are traces of decorative stucco work. Behind this are remains of two other massive imperial palaces, a small stadium and some baths, as well as the oldest remains in Rome, believed to date from the hut settlement established by Romulus in the eighth century BC.
By the first century AD the forum had become too small for the needs of the city and subsequent emperors erected their own fora which now lie on the other side of Via dei Fori Imperiali. Caesar, Augustus, Vespasian and Nerva each built a forum but, today, Trajan's is the most interesting to see because of the massive ancient shopping mall he built behind it. There were more than 100 shops here built on three levels, each area of the market specialised in one particular type of merchandise (such as fruit, fish or fabric). Next to the market is the spectacular carved column of Trajan depicting scenes from his successful empire-building campaigns.
At the far end of the Via dei Fori Imperiali lies the Coliseum, a symbol of Rome. It was built by Vespasian in 72 AD on land that had previously been occupied by the extravagant gardens of the hated Emperor Nero. It could hold about 50,000 spectators, who gathered to watch bloodthirsty contests between gladiators and wild animals. You can see the remains of the underground network of corridors along which the animals were freed into the arena. The cross was erected to commemorate the early Christians who are believed to have died here (although there is no evidence to support this belief). The beautiful arch beside the Coliseum was erected in the third century in honour of Constantine, although much of its decoration was pilfered from monuments to other emperors.
The Circus Maximus lies at the far end of Via di San Gregorio. There isn't much of it left although you can see the outline of the track around which teams of charioteers raced in competition. The tower at its south western end is medieval. Follow the road that faces this tower (Via delle Terme di Caracalla) to reach the baths of Caracalla. When they were finished, in the third century, they could accommodate 1600 bathers. As well as bathing, Romans came to the baths to exercise (there are remains of two gyms) use the libraries and shops, or just to socialise. There were baths of three temperatures, hot, cold and tepid. Until recently outdoor operas were staged during the summer amongst the remains of the hot baths.
