Under a withering Roman sun, legions of sunburned, sweating tourists loaded down with cameras and guidebooks plod dutifully from one "must" site to the next. A harsh Saharan wind slams through the narrow streets, churning up dirt, dust and tempers. Even the caged canaries who sing arias all year long from window ledges are numbed into silence by the merciless heat.

In the dog days of summer, the Eternal City can seem downright infernal.

But travelers take heart. You may not be able to find many air conditioners: Romans claim they're bad for your health and install them only in the most expensive hotels and restaurants as a concession to foreigners (read Americans). But Rome abounds with warm-weather pleasures and cool haunts (some of them haunted), especially for those who follow the path less traveled. And, for incentive, there's almost always a gelato around the next corner.

Many visitors go for a refreshing splash in Rome's famous fountains, although it's technically taboo under city law. Better to avoid the risk of a fine, and instead take a glide down the Tiber in one of the city's new shuttle boats. Or descend into the ice-cold caverns of the unearthly catacombs or an underground church.

The city offers many verdant retreats, from historic cemeteries to parks with rowboats. Swimming pools can be had -- for a price. At night, open-air entertainment is seeing a welcome revival. And one of Rome's most sublime summer pleasures is also the most simple: kicking back in the evening on a rooftop or terrace, sipping a glass of chilled vino bianco and watching the swallows dip their wings in the fading sunlight.

Allora, vive l'estate Romana (the Roman summer). But first, a few tips from people who live here.

Do (and Don't) as the Romans Do

The emperor Nero, it's said, fiddled while Rome burned. Even modern-day Romans rarely seem in a hurry, especially in the blaze of summertime heat. Few Romans run for the bus and work themselves into an unsightly lather. Take their cue and slow down those East Coast block-a-minute legs. Instead, you might try to emulate Roman males in late adolescence, those James Dean look-alikes with slicked-back hair and slow, slow swaggers. They never sweat. And they always choose the shady side of the street.

As for attire, Romans are generally good role models for selecting appropriate clothing for a hot city center, tending wisely toward lots of breathable cotton and linen. But women visitors should beware of emulating the super-short miniskirts favored by leggy Romanas: You will be chased right out of church, especially St. Peter's. Save them for other, more secular pursuits. As for men, keep your shirt on; not only are bare-chested men considered barbarians, they also chance a fine from city cops.

In some cases, indigenous logic can safely be ignored:

Do open the window in a crowded bus or tram, and ignore the muttered imprecations of the signora across the aisle. Contrary to popular belief, summertime correnti (drafts) will not cause sudden death.

Do take ice in your drink if desired. It won't ruin the digestion as your waiter insists. Nor will putting whipped cream atop a fruit-flavored gelato (another Roman no-no).

And yes, the water in Rome is perfectly safe to drink, in liquid or ice-cube form. The reason you see all those bottles of mineral water atop tables of dining Italians is that (a) it tastes better; (b) it's become part of the dining ritual; (c) it has snob appeal; and (d) the bubbles and minerals are held to do wonders for the digestive processes (just read the labels for long itemizations of beneficial effects on kidneys, pancreases, intestines, blood, liver... .).

Do visit in August. Despite the fact that many shops, restaurants and institutions take their holidays during the month, it's the most peaceful month of the year. Museums are uncrowded, streets blessedly free of traffic and the air untainted by noxious car exhaust.

Just watch out for major holidays. One of the year's biggest, the Feast of the Assumption -- or Ferragosto, as it's known here -- is celebrated on Aug. 15, and the city really does grind to a halt, with only minimal public transport and restaurant facilities available. The Rome newspapers La Repubblica and Il Messaggero print "survival guides" listing restaurants, pharmacies and other services that are open, but visitors would do well to retire to park or poolside and forget about accomplishing much sightseeing -- although most churches are open for services. With the city virtually empty of Romani, it'll be just you, other tourists and the legions of ghosts from ages past.

The City Underneath To beat the heat, ancient Romans retreated to mossy underground grottoes or garden summerhouses with fountains known as "nympheums," where they sipped wine and munched fruit. Undoubtedly, the coolest spot in all of Rome today is the extensive subterranean network of Nero's Golden House, or Domus Aurea (Via Labicana 136), where workers wear jackets in all seasons. There, the jaded and brutish autocrat whiled away summer days amid beautiful slave girls and the play of musical fountains. Unfortunately, the Domus Aurea can only be visited by applying to the Sovrintendenza Archeologica di Roma at Piazza delle Finanze No. 1. Drop by with your passport and they will process your request within a few days (note: groups take precedence over individuals). But there are many alternatives.

Topping the list is San Clemente, a fascinating layer-cake church in which you descend through time. It's located a long block away from the Colosseum on Via di San Giovanni in Laterano. Entering, you pass from an 18th-century facade to a striking medieval interior with lovely frescoes and mosaic floors. Go downstairs and you've suddenly passed through six centuries or so, to an early Christian church. Take another flight down and you're back in pagan Rome. The sound of water rushing through Rome's ancient drains is now all around you as you explore old Roman houses and vestiges of a cult temple. If you're lucky, you can tag along on a tour given by one of the Irish Dominican priests who act as caretakers. (If not, bring along the latest edition of Georgina Masson's "Companion Guide to Rome" {London, William Collins}, still the city's most informative and colorful guide, although the original was written 25 years ago.)

Another wonderful tiered church is found nearby, Santi Giovanni e Paolo on the Coelian Hill. It, too, features a descent into remarkable and extensive excavations of early Roman houses with surprisingly well-preserved frescoes. Once you've cooled off, the exterior is also worth a long look. From the square in front of the church, you will find that virtually no building visible dates later than the Middle Ages. (As Masson writes, "It is one of the few corners of Rome where a medieval pilgrim would have little difficulty in recognizing his whereabouts.")

Less notable, but a nice visit if you're in the fashionable old quarter of Trastevere across the Tiber, is the crypt of the lovely Santa Cecilia. Under the church are two Roman houses, one of which probably belonged to the martyred Cecilia. This church also features a pretty tree-shaded garden for resting.

Even Deeper There's nothing like a good chill running down your spine to take the edge off a hot day. And Rome, the ultimate city of the past, is brimming with the otherworldly and the macabre.

The Catacombs, the early Christian underground cemeteries that fan out in almost every direction from Rome, are a good place to start. In addition, at the Vatican, another well-preserved set of catacombs lies directly beneath St. Peter's Basilica. This often-overlooked necropolis contains the tomb of Saint Peter and what are believed to be the earliest mosaics from Christianity. An excellent tour in several languages is offered most days and is well worth the trouble of applying in advance. You can write to Prefettura Casa Pontificia, Citta del Vaticano 00120, or apply in person at the Ufficio Scavi (Vatican tourist office), directly under the Arco della Campana to the left of the basilica.

Of the principal Roman catacombs, three -- dedicated to Saints Callisto (Calixtus), Sebastian and Domitilla -- have regular, multilingual tours and can be crowded in season, while the other two -- under Saints Agnes and Priscilla churches -- are less-frequented. All are fascinating, but the Catacombs of San Callisto are in some ways the most impressive. A few miles down the Appian Way (Bus 118 from the Colosseum), they stretch over 14 miles and five levels, although only a fraction is open to the public.

We were taken down under one day by Brother Sylvester, a small and spry septuagenarian of the Silesian order. "A graveyard underground seems a very frightening thing for many people," he cooed before we left the sunlight. "I prefer to look at it as a bedroom for the dead, where they are sleeping... ." Inside there are thousands of graves carved out of the volcanic tufa stone, some with skeletons folded in, and a monument to the martyred St. Cecilia, whose marble statue shows two incisions on her long white neck. Explained Brother Sylvester: "They didn't just want to kill her. They wanted her to suffer. She bled for three days before dying." Although it's tempting to see more than the half-hour tour allows, it isn't advised to go off on your own. The kindly friar has a solution for straying guests: "I let them get lost and get a good fright, and then we come in and bring them out."

Earthly Thrills After this, you might need sustenance. Not far down the road is the fine restaurant Cecilia Metella (Via Appia Antica 125), with a shaded garden where you can feast on rosemary-roasted chicken and other local dishes.

While you're in the mood, you might want to continue out of the city, driving about an hour north to the hill town of Bomarzo, with its bizarre Garden of the Monsters. Far from the traditional assortment of flowers and hedges, these gardens appear to have been designed by a Renaissance man on the period equivalent of a wild acid trip. Scattered among the unkempt shrubbery and fountains are an assortment of grotesque statues, ranging from a colossal Hercules tearing apart a victim limb by limb, to a "chapel" decorated with death's heads, wild dogs, dragons and lions. The garden's history is shrouded in mystery, all the better for those with a taste for the eccentric.

Back toward Rome, you can stop for an evening of more thrills at Luna Park, in the EUR section south of the city, with its Ferris wheels, roller coasters and popcorn.

Shivers and Chills Within the city, one of the most unusual stops you can make is the church of Santa Maria della Concezione at the foot of the Via Veneto. Because of its unprepossessing facade, most people pass it by. But over the years it has gathered a growing group of devotees who know it simply as the Bones Church. Downstairs in its five cellar chapels are the bones of 4,000 Capuchin monks arranged in neat pyramids of skulls, tidy wall hangings of vertebrae and entire skeletons draped in their cowled robes.

Not far away, at No. 30 Via Gregoriana leading toward the Spanish Steps, is the 15th-century House of the Monsters, so-called for its singular facade in which huge, snarling gargoyle faces yawn over windows and doors.

If you're susceptible to shivers, you might try walking through Piazza del Gesu. It is often cooled by what locals call "the Devil's Breeze." Legend has it the devil stopped in one night at Jesuit headquarters and never came out. He might have taken a rear exit, but the breeze awaits him still.

You may also feel a prickle of goose flesh at the Gothic church of Sacro Cuore di Prati, with its special permanent exhibit dedicated to those unfortunate souls adrift in Purgatory. It's at Lungotevere Prati 12.

Finally, less spooky than utterly peaceful is the historic Protestant Cemetery at Via Caio Cestio 6. With its aura of 19th-century romance, thanks to the presence of the poets Keats and Shelley and solemn shade-bearing cypresses, it is a good place to relax among the spirits. Like many sites, however, it's closed during the worst heat of the day, around lunchtime. (A nearby landmark is the Pyramid of Caius Cestius, built by a 1st-century egotist, and forming along with the city walls the tiny, ice-cool Museo della Via Ostiense, one of Rome's many small museums off the tourist trail.)

The Pause That Refreshes When you've had it with sightseeing, nothing will do but a gelato. Luckily, you're in Rome, one of the few places on earth that boasts of ice cream made by "artisans."

The Pantheon area is ice cream heaven. Walk down Via del Pantheon and you'll hit one of the best on the right: Fiocco di Neve (Snowflake), a small, unpretentious ice cream parlor that offers everything from a delicious chocolate-rice confection to carrot or celery sorbet. Farther down on the left, when the street becomes Via della Maddalena, is the tony Gelateria della Palma, with some 100 flavors, tropical fruits being a specialty.

Around the corner on Via Uffici del Vicario is the city's most famous gelateria, Giolitti. They have flavors for every palate, with raspberry and melon special favorites. Not far away, on Piazza Navona, is the Gelateria Tre Scalini, with its infamous tartufo al cioccolato con panna, a diabolical frozen chocolate creation with whipped cream. It's worth skipping lunch for.

Lesser known, but a real Roman ice cream experience, is Fassi's Palazzo del Freddo (Cold Palace), not far from the train station on Via Principe Eugenio. With its high ceilings and vast proportions, the 110-year-old institution is a cathedral to the art of ice cream making -- even if its chocolate tartufi (truffles) and semifreddi (semi-frozen creams) are downright sinful. For a taste of the exotic, try Ristoro della Salute across from the Colosseum, with its rainbow of fruit flavors. If the gelato urge strikes after 9 p.m., head to the Selarum ice cream garden on Via dei Fienaroli 12, in Trastevere. There you can eat and listen to music until the wee hours. Also open late into the night is a stand serving delicious shaved ice doused in fruit syrup -- grattachecche -- on the Trastevere side of Ponte Garibaldi.

If your idea of refreshment is more along the lines of a double scotch or Shirley Temple, there are numerous bars with a view. Both the Cavalieri Hilton and Hotel Atlante Star offer panoramic views of Rome from their rooftop bars, as does the lesser-known but more intimate top of the Hotel Forum. The new Holiday Inn at Piazza della Minerva offers a scenic terrace from which you can spy over the roofs of the old city. Stopping at the chic, pricey Casina Valadier, which overlooks Rome from an edge of the Villa Borghese, is another relaxing way to spend the end of the day.

Open-air restaurants abound. Dining on a barge along the Tiber is one idea. Try the Canto del Riso or Isola del Sole. If you're feeling heavy from all the pasta, go for the green. One best bet is the lovely Vecchia Roma in the old Jewish Quarter, which offers a long and creative salad menu under 20,000 lire (about $18) and homemade fruit ices (graniti) for dessert. The trendy Il Melarancio features exotic salads and veggie dishes, as does the Centro Vegetariano Margutta. An economic alternative is to head for the salad bar at the frescoed McDonald's off Piazza di Spagna.

More Cool Ideas Idle down a shady street. The tiny Via delle Ceste, near the Pantheon, is a favorite. It's so damp and dark that moss grows there.

Enjoy the snow ... in August. Every year on Aug. 5, the faithful gather at Piazza Esquilino to commemorate the miracle of the Basilica of Santa Maria Maggiore (St. Mary Major). According to church history, the Virgin Mary came to a Roman patrician, telling him to build a great church where the snow fell in August. He did, and each year pilgrims are showered with jasmine blossoms or other forms of manmade "snow."

Go swimming. The nicest pools within city limits are also the most expensive: At the Cavalieri Hilton, the Parco dei Principi Hotel, the Villa Aldrovandi Hotel and other ritzy city pools, prices average 30,000 lire (about $27) to enter. For a budget (about $13 per person), family-style swim, the Oasi di Pace off the Via Appia Antica is an excellent retreat from the Rome caldron.

Take in an air-conditioned movie. Rome newspapers generally indicate which theaters are air-conditioned. Some even project outside in the summer. A few theaters offer English-language films.

Hop a boat. A shuttle boat, the Acquabus, runs all day until just before midnight, every day but Monday, with stops from Tiber Island to the Ponte Duca d'Aosta. One-way tickets cost only about 75 cents. Crewmen suggest you go from the afternoon onward, as the river level in the morning tends to be low (it's only about 10 feet deep anyway, and the dam upstream lets out water when needed, around noon). For information in Rome, call 686-0968.

Or take one of the highly recommended boat tours to Ostia Antica, the excavated port city that many believe rivals Pompeii as one of the surviving jewels of the ancient world. The Tiber II runs from Porto di Rira Grande each day at 9 a.m., returning about 4:30 p.m. The price of 42,000 lire (about $38) includes a guided tour of Ostia Antica. You can also dine on board for an extra 24,000 lire (about $21) apiece. Although reservations are not obligatory, Tourvisa advises visitors to call a day ahead to confirm the trip, at 446-3481 or 446-3482.

Go to the park. The sweeping Villa Borghese offers rowboats, horseback riding and the beauty of the Pincio, the public gardens looking over the city. Also suggested is the tranquil Villa Celimontana with its imported American squirrels and green canopied splendor, or the Parco Savello atop the Aventine Hill, which is blessed with magnificent views of Rome and at night is washed by orange blossom-scented breezes. The lush Botanical Gardens, tucked away on Via della Lungara, offers another green escape from Roman chaos.

In any season, it's well worth the 40-minute train ride north of Rome to Tivoli to visit the wonderful oasis of Villa d'Este, the Renaissance garden gem whose 100-odd fountains use water the way Michelangelo used stone. However, a continuing dispute among various tiers of Italian officialdom over the purity -- or impurity -- of the garden's water supply shut down the villa in the early summer, and may yet again. Check with the Rome tourist office or your hotel concierge before you head out, and in any case, don't drink the water.

The nearby Hadrian's Villa, a stretch of green dotted with ancient ruins, is a perfect spot for the imaginative and the romantic, and just a 40-minute bus ride from the center of Rome. Highly recommended.

Hear the music. Outdoor evening concerts are a traditional feature of Roman summers, from the Villa Medici to church cloisters. One treat this month will be a special program of Beethoven and Gershwin every night from Aug. 6 to 12 in the beautiful courtyard of Palazzo Baldassini, 35 Via della Correlle near Piazza Navona (call 556-1678 in Rome for reservations). Check the Rome newspapers La Repubblica or Il Messaggero for other programs, or the Rome tourist office at 461-851 or 463-748.

The summer opera at the Baths of Caracalla also is a delight. This August, "Aida" and "Swan Lake" are among the offerings. The box office at Piazza Beniamino Gigli 1 is open every day except Monday and weekday holidays (telephone in Rome: 461-755 or 463-641), and there is a special new telephone reservation service in English (6759-5721) that functions from 10 a.m. to 12:30 p.m. and 4:30 to 7 p.m. daily -- except Sundays, Mondays and weekday public holidays.

Escape the city. Plan a mountain trek in the beautiful Abruzzo National Park, only two hours from Rome -- or escape to the natural air conditioning of the underground Etruscan tombs at Cerveteri and Tarquinia. Enjoy dining on bruschetti (garlic toast) with tomatoes and clams in the sea air at Da Mastino restaurant in Fregene (45 minutes from Rome). For an evening alla starving artist, take the 30-minute bus ride to the hill town of Frascati. Enjoy a bottle of the local white and the mouth-watering porchetta (pork roast) sandwiches from its breeze-swept terraces as you watch the sun set over the Italian capital below. Jennifer Parmelee is a reporter based in Rome.