Seen from the air, set in its marshy context, surrounded by water and by a scattering of incoherent jigsaw bits of islands, Venice appears almost modest. Apart from the weather-vaned domes of the Basilica of San Marco and the city's emblematic campaniles (bell towers), with their peaked-hat capitals, it is a comparatively low-slung city; its red-tiled roofs seem dullish in comparison with the red-tiled roofs of the southern Mediterranean, as if they were permanently veiled in Adriatic mist; the unrelenting sinuous narrowness of the city's streets and most of its canals gives it a cramped, coiled-up feeling from above. (If you fly in from the east, Venice looks not just modest but vaguely comical—like some bloated cartoon version of the Italian boot itself, with the Arsenale, the city's historic shipyard, at the instep.)

Venice is not a modest city, of course, nor a dull (nor a comical) one. And it was not meant to be seen from the air. From sea level—from the water it tamed and ruled and turned into a kind of life's blood—it is nothing less than fantastical. Venice—Venezia, La Serenissima, The Most Serene Republic, conquerer of the eastern Mediterranean, cradle of elite democracy, artistic treasure-house, structural marvel, seducer, inspirer, tourist trap, the original Magic Kingdom—is the world's most unusual city. It is also the world's most romantic city, and quite possibly the world's most frustratingly schizophrenic city, too—for its mix of intrigue and cliche, of elegance and plastic tattiness, of art and kitsch. "Venice," Truman Capote once cracked, "is like eating an entire box of chocolate liqueurs in one go." It intoxicates; it cloys; it is irresistible.

Venice was one of the first cities in Europe to appreciate chocolate, as a matter of fact. It was also probably the first to enjoy coffee: A Venetian botanist and physician discovered the beverage on a trip to Egypt in the late 16th century and became the first European to write about it—and around 1615, Venetian traders started selling it in Europe for the first time. Venice may also have been the site of the continent's first coffeehouse.

Both chocolate and coffee figure in what has probably become the most famous of all Venetian dishes, especially in late pre-Millennial America: the dessert called tiramisu—which, in its purest form, is made simply by soaking spongy, elongated cookies (known as savoiardi to the Italians and ladyfingers to us) in black coffee, then layering them with mascarpone mixed with eggs and sugar and dusting the whole arrangement with cocoa. But while tiramisu may be Venetian, it is not old; it probably dates from only the middle of this century. The same is true of two other emblematic Venetian creations, carpaccio and the bellini—both invented at Harry's Bar, which opened only in 1931—and of a number of other specialties of the city. "Most of the dishes people think of today as Venetian," says Arrigo Cipriani, proprietor of Harry's, "are really rather new. Nobody ate risotto in the old days, only polenta and sometimes gnocchi. And almost everything used to be preserved—dried, or packed in salt or sugar, or marinated in vinegar."

Preserved foods (among them dried cod, dried beans, and pickled fish) are still important in the Venetian kitchen. In general, though, the city's cuisine—as it has evolved in our century—is delicate, straightforward, almost northern European in its sobriety. It is certainly not obviously luxurious: It isn't creamy, truffle-studded, or russeted with saffron; there are no gastronomic set pieces like the cappon magro of Genoa or the timpano of Naples; meat and game play a minor role. As Cipriani notes, the principal starch was historically polenta, which is the poor Italian's carbohydrate; when pasta was eaten, it was likely to be bigoli, made from whole wheat flour, which was cheaper and less highly regarded in the old days than refined white. There are certainly some strong flavors involved—one is the simultaneously earthy and briny pungency of squid or cuttlefish ink (which becomes a sauce for the cephalopod that yields it, and also, these days, darkens and adds savory richness to polenta, rice, and pasta); another is the salty, sweet-tinged sourness of sarde in saor (fried sardines with onions marinated in vinegar, often with raisins and pine nuts added), a genuinely ancient Venetian dish—but assertive elements are atypical. Garlic is an intonation rather than a defining statement in the cooking of Venice, for instance; tomatoes are used sparingly, and often in the form of paste or concentrate (the Venetian attitude towards fresh tomatoes may perhaps be divined from the fact that one local term for them is cirio—after a brand name for canned ones); cheese is relatively unimportant, not surprisingly, considering the Italian disaffinity for combining it with seafood—which is the meat of Venetian cooking.

Venice is an old city, founded (according to legend) in A.D. 421 by mainlanders from the hills and plains of the surrounding Veneto region, who took refuge on the islets of the lagoon from marauding Goths; or else (according to some history books) in a.d. 811 by residents of the nearby island of Malamocco, who were fleeing the approaching Franks. (Venetian ambiguity has deep roots.) In any case, the city takes its name from the Veneto—which today, by official definition, covers more than 18,000 square miles, reaching west almost to Bergamo, and north to encompass the Alpine ski resort of Cortina d'Ampezzo—and the region takes its name in turn from the Veneti, its pre-Roman inhabitants. (In 1581 Francesco Sansovino, son of the prominent architect Jacopo Sansovino, proposed that the name of the city in fact derived from the Latin exhortation Veni etiam, meaning "Come back again and again!" This may safely be considered an early example of chamber-of-commerce-ish folk etymology.)

The city's refugee-founders, whoever they were, cobbled Venice together from more than a hundred specks and hunks of water-bounded terra firma, sometimes joining them by shoveling dirt into the narrow passages between them, but as often canalizing the passages and linking the islets with bridges. Along the banks of the canals, they built palaces and warehouses on foundations of close-packed wooden piles, buried in silt (so that they didn't rot) and driven into a base of alternating layers of compacted sand and clay—an astonishing feat of engineering.

From the ninth through 15th centuries, ruled by elected doges (from the Latin dux, "leader") and the influential Council of Ten and Grand Council, Venice knew a golden age. It grew into a rich and powerful city, at one time holding sway over much of the old Byzantine Empire and sending its ships all over the eastern Mediterranean—and its merchants (Marco Polo was one) to the ends of the earth. Architecture thrived and the arts flourished. The façades of the palazzi facing the Grand Canal, whether gothic or otherwise, of gray marble or red stone, leafed in gold or tattooed with fine-lined tracery, are alternately stately, whimsical, sensual, wonderfully foreboding. (Ruskin wrote of Venetian gothic palazzi that "[T]hey wield over us an independent power," and that "Sea and sky, and every other accessory, might be taken away from them, and still they would be beautiful and strange.") The painters who set up their easels here—Bellini and Carpaccio (their names well known today to connoisseurs of the table), Mantegna, Tintoretto, Veronese, Tiepolo, Canaletto, and more—were great adventurers of color. Anyone who has ever seen the miraculous light of Venice, diffused but thick with texture, sometimes playful, sometimes achingly illuminating, will understand why.

Of course, golden ages always tarnish, and by the 18th century, Venice had grown blowsy and decadent, wormholed with intrigue, suspicion, and buffoonery. It became Las Vegas—consumed by gambling, famous for its prostitutes, a place where rules did not apply. In 1797 Napoleon took the city, disposed of the doge, and handed Venice over to the Austrians. Mass tourism followed a few minutes later, and the city became first a playground for the international rich and then a stomping ground for hordes of Kodak-toting vacationers. Now Las Vegas has become Venice: In 1999, a $2-billion hotel-resort-casino called The Venetian opened in the Nevada city, reproducing "the legendary city's most storied landmarks" (in surrealistic juxtaposition; the Rialto bridge crosses a car-filled "canal" and ends up next to the Campanile), and featuring the food of such old Venetian hands as Joachim Splichal and Emeril Lagasse. Massimo Cacciari, the mayor of Venice—the one in Italy—refused to give the place the city's endorsement. Now this, he said, was kitsch.

"When I was a teenager," says Paolo Barovier, a Venetian-born wine representative related to one of the oldest glassblowing families on Murano, "there were 200,000 Venetians. Today there are fewer than 70,000. The Venetian community has been lost."

Maybe so—more telling than mere population figures is the sobering fact that the average age of Venetian citizens today is almost 50—but Venice has a life beneath the surface: It is a secret city, a cult city, a fraternity of gondoliers, porters, concierges, shopkeepers, restaurateurs, all with their codes, their secrets, their real lives, all but impenetrable to outsiders. (The gondoliers, for instance, repeat the legend that scions of their dynasty—for it is that, a sinecure passed from father to son—are born with webbed feet, like geese, so that they can walk on water.) Part of the secret is the faintly lisping, vocally l-less Venetian dialect, probably nearly as intelligible to a visiting Catalan as to a Milanese (or Berlitz-trained American). Even the streets have their own language, Spanish-inflected and evocative: A calle, as in Spain, is a street; a rio (Spanish for river) is a canal, and a rio terra is a canal filled in and turned into a little street. A fondamenta or a (usually broader) riva is a street that runs alongside a canal. As elsewhere in Italy, a campo is a small square—but so, sometimes, is a piscina. (Venice has only one piazza, that of San Marco.) A corte is a courtyard, and a sotoportego or sotoportico is a covered passageway. A ruga—from the French word for street, rue—is (or was originally) a commercial street.

To catch at least a passing glimpse of the secret Venice, visit the city in winter. Venice is always wondrous: Its very premise—a faded empire built on water, bathed in damp light, ruled by the tides—is a fairy tale; its ancient streets, pathways in history's most beautiful maze, evoke both mystery and metaphor; its rhythms, slow and sly and sometimes racy, stir the jaded heart—even in the humid, humanity-clogged midst of summer. But winter is something else. The Venetian light grows even softer than usual, and the old stones of the city seem more finely etched, more clearly defined, in contrast. The pace stays calm, but there are hints of an unguarded jauntiness among the locals and the regular visitors—as if the thinning of the crowds has made it possible to swing the arms a little, and cock the head in appreciation, or good-natured skepticism, now and then.

There are tourists in winter, of course—in Venice, there are always tourists—but they are more sparsely distributed, and seem somehow less frenetically driven, less programmed by their guides or guidebooks, than the tourists of July. There is room to walk, room to look; there are few lines in museums, few rush-hour clots of people on the vaporetti (the "buses" that ply the canals). Some restaurants are closed for a month or so in winter, usually in January, but plenty of others are open, and they may betray an easy camaraderie that they lack the time and spirit for in July.

And winter, surprisingly, is a good time to visit the famous Venetian markets near the Rialto bridge—at which the raw materials that provision local kitchens and ennoble local tables are displayed in all their splendor. The fish market may admittedly be stocked with what is, by local standards, a relative paucity of sea creatures at this time of year, and much of what's there is miniature in scale. ("We fish large quantities of small things," one Venetian told me.) But even so, the variety and cheeky freshness of the fish and shellfish here—the glistening scampi, the shiny turbot, the tiny squid and cuttlefish lurking in their ink, the plump eels writhing slowly in Styrofoam boxes, and the rest—puts American fish markets to shame. And in the produce market nearby, there is a surprising array of vegetables, many of them essential to Venetian cooking, and at least some of them grown in market gardens on the islands of the lagoon.

Above all, everywhere, there is radicchio. Or rather there are radicchios: not just the round kind, called chioggia (after the fishing port at the south end of the lagoon, near which it was developed)—so common in America today that even McDonald's puts it in its salads—but also late-season radicchio di treviso (called tardivo), elongated, with long stems and sparse, loose leaves; radicchio bianco, round but almost white, with faint pink-brown markings; and the elegant radicchio di castelfranco, with pink-and-yellow leaves, as jauntily blowsy as those of boston lettuce. In January, too, there is broccoli, which the Venetians call amorini, and baby cauliflower (its florets almost completely concealed by a thicket of ribs and leaves), which the Venetians, doubtless with some ancient logic, call broccoletti. There are cranberry beans from Lamon, in the Veneto province of Belluno, considered here to be the best of all beans for their sweetness and obligingly tender skin. There are even early castraura, "castrated" artichokes—so called because they're the first buds, cut from the heart of the plant—a precocious harbinger of spring.

Winter is also, of course, the season of Carnevale in Venice. Whether this is a good thing or not can be debated. Whatever its historical antecedents (there are records of a pre-Lent celebration in the city as early as the 11th century), today's Carnevale—which takes place each year over the ten days preceding Shrove Tuesday—is an invention of the late 20th century, dating only from 1979. "For the first five or six years," says the Count Brandino Brandolini, who lives in a palazzo on the Grand Canal, "Carnevale was wonderful. It was just a few thousand people milling around San Marco with some wine and some music—all very natural and spontaneous. But now it has become very commercial. Now there's one person in costume and ten people to take his picture." This Venetian secret has been given away.

It seems ingenuous to propose that Venice is defined by water; of course it is. (The Round Table wit Robert Benchley, upon arriving in Venice, famously wired a friend "Streets flooded. Please advise.") What might still surprise the visitor, though, is the extent to which the canals, and above all the Grand Canal—which has been called the world's most beautiful street—are living, breathing, working waterways. Stand on the riva degli Schiavoni, say, on a weekday morning and stare out at the traffic: not just those legendary gondolas (built asymmetrically so that they'll travel in a straight line when poled from only one side), but also the canal-crossing gondola-ferries called traghetti (Venetians always stand up in them—in all boats); elegant, long water taxis with polished wooden hulls; no-nonsense Guardia Costiera outboards powered by twin Johnson 70s; slow-moving burci (delivery barges); workaday vaporetti full of both tourists and locals … This is no meandering stream; it's a bustling boulevard.

The canals are the arteries of Venice, cleansing the city, provisioning it, keeping it alive. But the canals are only part of it. What defines Venice most of all—gives it its shape, its limitations, its possibilities—is the lagoon. It is seawater flowing into the lagoon from the Adriatic, and from the lagoon into the canals, that keeps the city from literally stagnating. (The same tidal incursions, of course, also flood the city frequently, and have been eroding it since it was built.) And the lagoon gives Venice its best fish and shellfish, and its most flavorful vegetables—grown in market gardens on several islands. "The best things you can eat in Venice," says Arrigo Cipriani, "all come from the lagoon, not just the seafood but the vegetables. Because of the slightly salty ground, things grown on these islands have a special character."

"Everybody who comes to Venice," says Mauro Stoppa, "knows the canals. But they almost never notice the lagoon, even when they travel to Lido or Murano." Stoppa is an agronomist by training, and owns a company that manufactures horticultural machinery—but by birth he is a creature of the Venetian lagoon. Though he now lives in the Colli Euganei, the green volcanic hills above Padua, 20 miles or so west of Venice, Stoppa was born to the south of the city, near Chioggia—the area's main fishing town—and has sailed, fished, and hunted on the lagoon all his life. "The lagoon," he says, "is my sea."

In hopes of fostering greater respect for the lagoon, Stoppa bought a 53-year-old, 52-and-a-half-foot Chioggia-built bragasso, a traditional-style fishing boat whose design dates back to the days of the doges. He restored and upgraded the craft, and christened it the Eolo (for the Greek god of wind)—and now he takes people out, for one day or three, on food-and-lore cruises through the whole vast aquatic system.

We set out with him for an evening cruise at 5 p.m. on a beautiful, warm summer evening. On board, besides us and Stoppa, are Pierre Lasserre, a marine biologist just appointed UNESCO director-general for the Venice region, and his wife, Bernadette; Angelo Marzollo, a professor of applied mathematics from the University of Udine in Friuli, who works as a UNESCO advisor in the lagoon, and his teenage son Toniis; Antonio Fiorentini, a one-man crew who also owns Venice's only nautical bookshop; and Stoppa's sisters Lucia and Julia, who are helping him cook tonight.

Gliding off, we cruise past San Clemente, where pilgrims headed for the Holy Land used to stop for succor, and where the doges once welcomed visiting dignitaries. Next we put in at Sacca Sessola, once the site of a self-sustaining tuberculosis hospital, complete with electric generators; acres of farmland and vineyards (the soil is very fertile, and the temperature is a few degrees warmer on the average than that of Venice); a winery; a church; a school; and living quarters for hospital staff and the families of patients. We trek around the island for an hour or so, and discover an unexpected side of Venice—passing olive and palm trees (less than a mile from San Marco!), magnolias, oleanders, lebanon cedars, eucalypti, mulberries. For the first time, we feel as if Venice has a truly Mediterranean aspect.

Leaving the island, we navigate the lagoon, and about half an hour later, drop anchor between tiny San Francesco del Deserto (site of a Franciscan monastery where only eight monks live) and Sant'Erasmo, the largest island in the lagoon and the most agricultural. From the Eolo, we can see low stone walls, inset here and there with locks opening into drainage channels, and behind them low vineyards and rows and rows of spiky artichoke plants. At a beautifully set table on deck, we consume a perfect lagoon-derived Venetian meal. First there is the meat of sprawling spider crabs gratineed with thyme-scented bread crumbs—"a dish my mother used to make," says Stoppa. Next comes a classic Venetian risotto, flavored with a puree of the little lagoon fish called go—which is goby or gudgeon—boiled with white wine and vegetables, then passed through a food mill. The main course is a magnificent branzino, or sea bass, baked in the Eolo's little oven. "Fish of this quality," says Stoppa, "even the best restaurants can't usually get. There just isn't enough caught every day. I buy directly from a fisherman. Sometimes when we're sailing out in the evening, he's coming back in and sees the boat, and stops then and there to sell us something."

Eating this excellent repast, surrounded by the land and fishing grounds from which it comes, we could hardly feel more intimately connected with the lagoon—and, through the lagoon, with Venice itself.