This tremendous theatrical space, centred on the gleaming marble composition of Bernini's Fontana dei Quattro Fiumi (Fountain of the Four Rivers), is the hub of the centro storico.
For centuries, piazza del Popolo was the first glimpse most travellers got of Rome, for it lies at the end of the ancient via Flaminia and directly inside the city's northern gate the Porta del Popolo
The Pantheon is the best-preserved ancient building in Rome. It was built (and possibly designed) by Hadrian in AD 119-128 as a temple to the 12 most important classical deities.
Home to the Italian Senate since 1871, this palazzo was built by the Medici family in the 16th century as their Rome residence.
Vespasian began building the Colosseum - which has hosted gory battles between combinations of gladiators, slaves, prisoners and wild animals of all descriptions.
After its period of glory, the Forum was relentlessly attacked for centuries by barbarians, after which it was gradually dismantled by anyone - from popes to paupers - who needed building materials.
On the north-east side of via dei Fori Imperiali are the extensive remains of Trajan's forum, the last of the fora, laid out in the early second century AD.
For recent generations, it was Anita Ekberg who made this fountain famous when she plunged in wearing a strapless black evening dress in Federico Fellini's classic La dolce vita.
The 30m (100ft) column of Marcus Aurelius was built between AD 180 and 196 to commemorate the victories on the battlefield of that most intellectual of Roman emperors.
The oldest and largest of Rome's ancient arenas, the Circus Maximus hosted chariot races from at least the fourth century BC. It was rebuilt by Julius Caesar to hold as many as 300,000 people.
Begun by Emperor Hadrian in AD 135 as his own mausoleum, Castel Sant'Angelo has variously been a fortress, prison and papal residence.
The lavish late 19th-century teatro all'italiana interior comes as quite a surprise after the grey, angular, Mussolini-era façade and its esplanade with tacky potted palms.
Great for all types of performances, the Olimpico has good acoustics, even for cheaper seats. Go for the central front and second row seats in the gallery.
This new film space in a restored pavilion in the Villa Borghese park is used for cinema-related presentations, but also has its own screening schedule, organised around themed days of the week.
After 120 years as a building site, the current St Peter's was consecrated on 18 November 1626 by Urban VIII - exactly 1,300 years after the consecration of the first basilica on the site.
The current 16th-century church of this magnificent religious complex was built above a fifth-century basilica, which in turn incorporated a titulus, or house where early Christians met.
First mentioned in 431, the church was rebuilt in 439 by Sixtus III with backing from Emperor Valentian III's wife Eudoxia, and dedicated to Saints Peter and Paul.
This 12th-century church was built on the site of a titulus, which in turn is believed to stand on the site of an ancient well sacred to Juno. The church's exterior incorporates Roman columns.
Along with the Lateran palace, it was the site of the original papal headquarters until the move across the river to St Peter's and the Vatican in the 14th century.
It's a relief that Augustus' great monument has finally been liberated after years hidden beneath scaffolding: its Luna marble glows in architect Richard Meier's luminous space.
