From the Colosseum to the Sistine Chapel, from Trevi Fountain to the Spanish Steps, Rome's headline acts need no introduction. But away from these historic crowd-pleasers, there are a host of lesser-known sights and neighbourhoods waiting to be discovered. Here's a selection of our favourites.
On a quiet side street near the Basilica di Santa Maria Maggiore, this small, easy-to-miss church is a gem. From the outside it looks nothing special, but venture in and you'll be bowled over by some of Rome's most dazzling Byzantine mosaics. The 9th-century apse designs are beautiful but for a full-on, jaw-dropping spectacle, check out the Cappella di San Zenone. Also in the chapel is part of the column to which Christ was supposedly tied when he was flogged before the crucifixion.
An ornate Mannerist palace near Campo de' Fiori, Palazzo Spada harbours one of Rome's most famous architectural follies. At first sight, the Prospettiva del Borromini (Borromini's Perspective) looks just like a lengthy gallery leading to a life-size statue of a Roman warrior. In fact, it's an optical illusion and the corridor is only 8m, rather than the 35m or so it seems, and the statue is merely hip height. To achieve the effect, architect Francesco Borromini used a rising floor and converging rows of shortening columns.
For a little light relief from Rome's heavyweight sights, take a stroll in the Quartiere Coppedè, northeast of Villa Borghese. This pocket-sized district, designed in the 1920s by a little-known Florentine architect, Gino Coppedè, is a fairytale mishmash of turreted villas, towers, gargoyles, arches and graceful palm trees. To access the area, go through the monumental arch on Via Tagliamento to Piazza Mincio, home of the charming Fontana delle Rane (Fountain of the Frogs).
The Museo Nazionale Etrusco di Villa Giulia is one of Rome's great unsung museums. Housed in an elegant Renaissance villa, its superb collection of Etruscan treasures provides a fascinating introduction to the mysterious people who ruled central Italy before the Romans. Must-sees include a 6th-century BC tomb, the Sarcofago degli Sposi (Sarchophagus of the Betrothed), and the terracotta Apollo di Veio.
To enjoy a bit of local colour, head to Garbatella, a lively neighbourhood off Via Ostiense. The quarter was built in the 1920s and 30s as a garden suburb for city workers and still has an earthy, unpretentious feel. Architecturally, it's a weird hotchpotch with everything from low-rise villas to community gardens, faux baroque palazzi and large housing blocks known as alberghi suburbani (suburban hotels). Signature buildings include the Albergo Rosso and Teatro Palladium, focus of the area's thriving cultural scene.
Overlooked by the ancient pyramid Cestia, the Cimitero Acattolico (Non-Catholic Cemetery) is a verdant oasis of peace in the bustling Testaccio district. An air of Grand Tour romance hangs over the site where up to 4000 people lie buried, including the English poets John Keats and Percy Shelley, and Italian political thinker Antonio Gramsci. Outside the cemetery walls, Testaccio is a top spot for night-life (Roman Movida, night clubs and discos) and a taste of nose-to-tail cuisine. Many of Rome's trademark offal dishes originated in the area, and there are any number of trattorias still serving them, including longtime favourite Da Felice.
Few people make it to this haunting 5th-century church, but those who do rarely forget it. Hidden in its own secluded grounds near Villa Celimontana, it's a handsome, beguiling place with a porticoed facade and a round, columned interior. But what really gets the blood pounding is the wall decor - a cycle of 16th-century frescoes depicting the tortures suffered by many early Christian martyrs. Describing them in 1846, Charles Dickens wrote: "Such a panorama of horror and butchery no man could imagine in his sleep, though he were to eat a whole pig, raw, for supper".
In the far south of the city, the EUR district is a world apart. Spacious and stridently modernistic, it was built for an international exhibition in 1942 - hence its name, Esposizione Universale di Roma (EUR for short) - and boasts some superb modern architecture. A highlight is the Palazzo della Civiltà del Lavoro, a masterpiece of Italian rationalism known locally as the Square Colosseum. Also in the area, the Museo della Civiltà Romano has a fascinating room-sized model of 4th-century Rome.
Like a Roman version of London's Tate Modern, the Centrale Montemartini is a former power station turned art museum. It was originally established as a temporary outpost of the Capitoline Museums, but it has since become permanent and now displays the overspill from the museums' vast collection of classical statuary. Explore its echoing halls and admire ancient sculptures starkly juxtaposed against hulking diesel engines and huge steam boilers.
Rome's Cinecittà film studios are steeped in movie history. Liz Taylor and Richard Burton first met here - on the set of Cleopatra - and more than 3000 films have been made on its huge lots, including Ben Hur, La Dolce Vita and Martin Scorsese's Gangs of New York. Visits take in exhibitions dedicated to famous costumes and sets, as well as actors and directors who have worked here.
Even in a city as photogenic as Rome, few places are as picture-perfect as the courtyard behind the Arco degli Acetari (Vinegar-Makers' Arch; Via del Pellegrino 19). The arch itself is dark and not especially inviting, but duck under it and you emerge onto a tiny medieval square enclosed by rusty orange houses and full of cascading greenery.
Named after St Francis, who is said to have once stayed here, this seemingly unremarkable Trastevere church is home to an extraordinary work of art. Gian Lorenzo Bernini's sculpture of Beata Ludovica Albertoni oozes sexual ambiguity in its depiction of the cloaked saint lying back in the throes of religious ecstasy.