An insider's guide to Italy has singled out the country's best under-the-radar destinations, from the Veneto's Prosecco Hills to the volcanic Aeolian Islands, while flagging the overcrowded spots worth avoiding in peak season.

The guide comes from a travel writer whose grandfather was from Liguria and who has lived in Venice, Sicily and Marche. According to the writer, no country matches Italy's diversity, even though its popularity means the main sights can become unbearably crowded in high season. The advice is to pair a big-hitter attraction with a lesser-visited spot nearby, and to build in extra days around crowded destinations.

Veneto Beyond Venice
Everyone should enjoy Venice's canals and historic churches at least once, but the guide urges travellers to leave time for the wider Veneto region. Padova has the Scrovegni Chapel, frescoed floor to ceiling by Giotto; Verona's pink-stone amphitheatre is one of many Roman ruins; and Vicenza is lined with Renaissance palaces. The Prosecco Hills offer tastings at most wineries. Tip: break up sightseeing with a beach day on Jesolo's long Adriatic sands. A seven-night walking holiday in Veneto costs from £1,699pp including flights, half-board accommodation in Padova, transfers and luggage, via Involved Holidays.

Sicily's Beaches and Ancient Ruins
Sicily, the guide says, is having a well-overdue moment, offering beaches such as the Zingaro reserve, Greek remains at Syracuse and Agrigento, the mosaic-covered Villa Romana del Casale, Norman castles, Baroque palaces and the active volcano Etna. Capital Palermo blends all of it. Tip: head inland to hilltop towns such as Enna or Baroque Noto. An eight-day escorted tour of Sicily, taking in Palermo, Agrigento and Villa Romana del Casale, costs from £1,339pp including flights, transport and guides, via Cosmos.

Rome's Ancient and Renaissance Sides
Beyond the city-centre sights, the guide recommends the 2,000-year-old Appian Way, lined with tombs, catacombs and the Villa dei Quintili estate, along with Renaissance-era art at Palazzo Barberini and Villa Borghese. Tip: see the Roman Forum before the Colosseum, since one ticket covers both but Forum queues are shorter. A seven-night Rome and Florence twin-centre holiday costs from £979pp B&B, including flights to Rome and back from Florence, private transfers and first-class train travel between the cities, via Tropical Sky.

Tuscany's Val d'Orcia
Southern Tuscany's Val d'Orcia, with its rolling hills and cypress avenues, begins near Siena, whose Renaissance art rivals Florence's. The Crete Senesi landscape leads into hilltop towns Montalcino, San Quirico and Pienza. Tip: descend into Montepulciano's 'cathedral of wine', a vintners' cellar dug into the hillside at the De' Ricci vineyard. Seven nights at Borgo Tre Rose, a vineyard 20 minutes from Montepulciano, cost from £645 including flights, via Citalia.

Puglia's Salento Peninsula
Rather than the rockier Adriatic side of Puglia's heel, the guide points travellers to the Salento peninsula for sandy beaches such as Porto Cesareo, Baroque towns such as Nardò, and the fishing town of Gallipoli. Tip: add an overnight in Matera, a UNESCO World Heritage site across the border in Basilicata, sleeping in a cave hotel cut into the cliffside. Three nights' B&B at Tenuta La Baronessa Resort in Gallipoli costs from £328pp including flights and coach transfers, via Tui.

Pompeii and Herculaneum
At Pompeii, visitors can walk into ancient houses, visit the baths and see the Roman equivalent of a fast-food counter. Nearby Herculaneum, destroyed by the same 79AD eruption of Vesuvius, was once a seaside resort for wealthy Romans, and its ruins are packed with detail, including mosaics and preserved door frames. Both sites sit around 30 minutes from Naples, home of Neapolitan pizza. Tip: take the free Artebus shuttle from Pompeii to the Roman villas at Oplontis and Castellammare di Stabia. A seven-night twin-centre break between Sorrento and Capri costs from £1,599pp including flights, transfers, a hydrofoil to Capri, two nights' B&B in Capri and five nights' half-board at the four-star Jaccarino hotel near Sorrento, via Citalia.

Italy's Northern Lakes
Northern Italy's glacial lakes have drawn visitors since Roman times. Lake Como suits five-star stays in lakeside villas turned hotels, while Lake Garda offers a more active break, with road trips, cycling round waterside villages, Roman remains at Sirmione and the Valpolicella wine country nearby. Tip: stop at Lake Iseo, between the two, for a quieter alternative. Seven nights at the La Paul hotel on Lake Garda cost from £485pp room only, including flights and private transfers, via easyJet Holidays.

The Dolomites
The jagged peaks and plateaus of the Dolomites, in north-east Italy, are best explored in summer by road trip, on foot, or by cable car up to mountain-top rifugi. The area between Cortina d'Ampezzo and Ortisei is the most spectacular, though Alta Badia makes a laid-back base. Tip: for some of Italy's best views and easy walks, try the Alpe di Siusi plateau above Ortisei. A seven-night summer stay in Alta Badia costs from £1,533pp including flights, transfers and half-board accommodation at Sporthotel Panorama, via Inghams.

Bologna's Food and Architecture
Bologna, Italy's food capital, serves tortellini in cream and tagliatelle al ragù, but its 25 miles of porticoes, leaning medieval towers and history of female Renaissance artists are worth exploring too. Modena and Parma make easy day trips. Tip: visit Ravenna, the final capital of the Western Roman Empire, for some of the world's finest Byzantine mosaics. A seven-night trip to Bologna, Parma and Ravenna costs from £1,688pp including flights, airport transfers, train tickets and a walking tour of Bologna, via Kirker Holidays.

Liguria's Cinque Terre Coast
The coastline from La Spezia to Levanto takes in Cinque Terre, five fishing villages spilling down the cliffs, and Portovenere, along with Lerici, once home to Percy and Mary Shelley, with its quiet bay and medieval castle. Tip: avoid weekends and Italian holidays, when the area gets packed. Three nights at Grand Hotel Portovenere cost from £1,298pp B&B including flights and transfers, via Kirker Holidays.

The Aeolian Islands
With crowds drawn to Sicily's Egadi Islands this year, said to be film-maker Christopher Nolan's Ithaca, the guide recommends the Aeolian archipelago instead: seven volcanic islands including picturesque Salina, upmarket Panarea and black-sanded Stromboli, an active volcano that puffs roughly every 15 minutes. Tip: use Lipari as an island-hopping base. Seven nights at Hotel Mea on Lipari cost from £1,105pp B&B including flights, private transfers from Catania and the hydrofoil, via Kuoni.

Marche's Hills and Beaches
The Marche region, on the Adriatic, has rolling hills, medieval towns and beaches, from the resorts of Fano and Pesaro to the wild Riviera del Conero, home to the Spiaggia delle Due Sorelle. The Renaissance city of Urbino is the main draw, alongside hilltop Treia and Ascoli Piceno. Tip: add a day trip to San Marino, the world's fifth-smallest country, a 70-minute drive from Urbino. Three nights at Gallery, inland from the beach town of Senigallia, cost from £598pp B&B including flights and car hire, via Kirker Holidays.

Umbria's Hill Towns
Italy's 'green heart' has rippling hills, mountains and medieval towns such as Spello, decorated with Renaissance art. Perugia holds works by Raphael and Perugino, Montefalco produces sagrantino wine, and Assisi, home of St Francis, has frescoes by Giotto in its basilica. Tip: seek out under-visited sites such as the Roman town of Carsulae and the fossilised forest at Dunarobba, one of only three in the world. Four nights at Borgobrufa Spa Resort outside Assisi cost from £853pp B&B including flights from Heathrow, via British Airways Holidays.
Florence's Art Scene
Florence, where the Renaissance began, is unmatched for art, according to the guide. Beyond the Uffizi and the Accademia, its quieter museums, including the Bargello, Orsanmichele and Casa Buonarroti, home to small sculptures and models by Michelangelo, are more atmospheric. Tip: skip the Duomo's interior but climb to the rooftop through Brunelleschi's dome. Three nights at Palazzo Lorenzo Hotel Boutique and Spa cost from £329pp B&B including flights from Gatwick, via easyJet Holidays.

