Master class with Argentina's master photographer, Aldo Sessa, turns a tour of Buenos Aires into a lesson in beauty, history, and the perils of perfection.

When Aldo Sessa undertakes to show you "his" Buenos Aires, he does so in true Porteño style: with elegance, charm, and passion, and perhaps a bit of mania. Driving with Aldo can feel like being in a video game. But, really, why should he trifle with merging traffic, curbs, or, for that matter, oncoming city buses, when his city has so much to offer that you must see it all now?

Aldo reigns loosely as Argentina's most famous photographer. He has produced more than 30 books, among them Tango, Buenos Aires Panorama, and Gauchos, which collectively have sold about 300,000 copies. He's shown his photos and drawings in dozens of countries, collaborated with Ray Bradbury and Jorge Luis Borges, and not long ago shot a commercial with Antonio Banderas for Parliament cigarettes. "I've never seen anyone who could smoke like Antonio," Aldo says. "He is a fabulous smoker."

Aldo has recently begun to offer a one-day, $1,000 class. His Web site describes it as "a different cultural activity for VIP visitors, lovers of photography" who want to experience the "off-the-beaten-track" Buenos Aires. Whether you want to go to the Jardín Japonés, Evita's tomb, Puerto Madero, or perhaps a raucous demonstration in the city center, Aldo, who speaks fluent French, English, and Italian, can take you there and give you one-on-one assistance, technical or aesthetic.

I signed up for the class ostensibly to improve my photography skills—which I'd characterize as more interesting than consistent—but my deeper rationale is that I haven't seen Buenos Aires in 15 years. When I was a kid, my family made several pilgrimages to visit our ravishing, ultrathin cousins, Michele, Karin, and Mumi. But the supernova level of drama (breakups, divorces, drug-addicted boyfriends, torched houses) outshone the city. There was no Buenos Aires, only the cousins and the crisis del día. So even though I feel that I know Buenos Aires (the pace, the food, the ways to grimace and flirt), I want a tour guide...who isn't a member of my family.

Aldo greets me at his sleek, modern studio in Palermo (the coolest, quaintest part of the Porteño counterpart of SoHo). He's dressed in a white polo shirt and black jeans, with a loupe hanging on a string around his neck like a bolo tie. He has a handsome face, pleasant, sensual, good-humored, and far younger-looking than his 64 years.

We spend an hour drinking coffee, eating rolls called medialunas, and looking at his books. I learn that he worked for four years on Gauchos, and five on a series on the Teatro Colón, his study of the national opera house, for which he took more than a million photos. Aldo favors black-and-white and high contrast—the gauchos are more elegant than they have a right to be—but a certain melancholy comes through even in the most prettied-up compositions.

When he asks me about my photographic goals, I shrug; it's embarrassing, but I really don't know where I want to go. Aldo suggests that we visit the Rosedal, or Rose Garden, which, like many of Buenos Aires's parks, was designed by the French botanist and landscape architect Charles Thays. And then, without further ado, Aldo hands me a Leica. I've been hearing about Leicas for years, but I've never gotten to play with one. Suddenly, I feel muy VIP.

It's wintertime, so the roses are dormant, but the park is still exquisite. At the entrance, we pass a pavilion, a semicircle with smallish busts of third-rate writers no one's thought about in 50 years, in or outside of Argentina. Aldo launches into a mild tirade about the folly and fulsomeness of busts—busts in parks, busts made on the cheap, and finally, cheapness in general. I like this man.

He tells me about his friendship with the writer Manuel Mujica Láinez, now dead and best known for a work of science fiction called The Wandering Unicorn (1965). "He was very aristocratic, and he had excellent taste." Together, the two men explored the city, Láinez showing Aldo his favorite sculptures by Rodin and Bourdelle, but encouraging him to remain ever alert to the city's subtler, weirder aesthetic pleasures.

Aldo takes my arm. "And after that, I kept learning. For example: trees. I've come to adore trees. I did an entire book on trees. They became an obsession. Did you know that all trees are people?" He points nearby. "Look at this palo borracho." It's a crazy-looking tree (hence the name, "drunken stick"), not unlike a baobab, except that it's covered in razor-sharp thorns. Aldo points to some knots. "Look at the Picasso eyes on it." The knots do look just like the eyes of a woman in a Cubist painting. Aldo points to one tree after another. "This one is a big hand, reaching up from the earth. This one's a woman's body. The hole in this one is a belly button. No?"

We spend a quarter of an hour photographing trees, and the morning, which began with rain, gives way to bright sunshine and mercury-limned clouds. Aldo inhales happily. "I breathe light. Of course, I love the sunset the most. If I could freeze the light forever at that time of day, I would."

Back into his SUV. Back into the scary traffic. We pass a large bank. Aldo points out where the plate-glass windows have been replaced with sheet metal for security, knocking out, as he does so, an entire row of construction cones. We pass a family dressed up as clowns, performing tricks at an intersection; since the currency collapse of January 2002, tumblers such as these have become a city staple. Perversely, even as Argentina's economy declines, the city retains its beauty: the French- and Spanish-inspired architecture; the splendid boulevards lined with jacarandas, Canary Island palms, and eucalypti.

Aldo screeches into La Boca, the old port, formerly home to poor Italian immigrants. There's a brief altercation with a bus driver, which ends when Aldo advises the man, "Hey, if I want to go, I go, eh?" We park. The wood and tin houses are gaily painted with festive, colonial-era pastels, which helps hide the fact that many of them are rusting and teetering. Aldo calls them casas torcidas, or twisted houses. One time, he tells me, a man approached him when he was taking pictures here and said, "You like these houses?Why don't you try living in one of them?" I nervously sneak a picture of a man leaning out of a window.

It's well past lunchtime when we duck into San Babila trattoria in Recoleta. It's amazing that Argentines aren't as fat as houses, what with the constant red meat and the fact that after Italians, they may consume more pasta per capita than anyone else in the world. An itinerant photographer wanders up and asks to take our picture. When he recognizes Aldo, he flushes bright red and almost prostrates himself. "Oh my. I didn't recognize you." Aldo laughs and says, "He's actually much better than I am. He's just more modest."

The next stop is the Teatro Colón. Aldo seems to quicken. It's admirable that after spending every night here for five years, he's enthusiastic about returning. Unfortunately, we're too early. The doors are closed. Aldo prowls around, looking for a way in. "I'm going to push some buttons," he says, disappearing behind a security gate. He emerges two minutes later with an usher, and we're in. It's gorgeous. Soon, it will be more so. The house is being restored for the first time since its construction in 1908. A full orchestra practices in one chamber with enormous chandeliers and wall-length mirrors. Onstage, a production of Massenet's Manon is in rehearsal.

Aldo's attention is everywhere but on Manon. He points to the domed ceiling: "When Perón was president, one summer was very hot, and so he brought two hundred blocks of ice to put up there to cool the place. Can you imagine?"

Aldo leads me out of the theater and points to a banister. It's made of beautiful, yellowing marble. "Do you see the fossils?" Upon closer inspection, I do—polished slices of prehistoric snail shell. They're luminous, like phosphorescent plankton. I imagine there must be season ticket-holders who have been coming here forever and do not know about this. Would I, if I hadn't come with Aldo?

He smiles. It's the kind of lesson in aesthetics he must have received from his mentor. "Buenos Aires has none of the big things of New York, Paris, or London. What makes it special is all the little things. The small sights, the subtle things, the places where the cultures mix, where the English meets the Arabic and the French and the Spanish just así. That's what you're looking for."

He checks his watch. "Come on. Do we want to see Evita?There are all these abandoned cats near her tomb. They're very well taken care of. I think you will love them."

Just as we leave the stairwell and enter the main foyer, I smell it: The Smell. I've never known what it is, but Argentina and gifts from there all seem to have it. It's a pleasant, resinous sort of smell, like an old violin. My guesses over the years have included certain kinds of varnish and, of course, leather. I still don't know. The Smell unlocks some inner treasure trove of nostalgia, and fondness, a world-weary appreciation for elegance and decay. Come to think of it, this is what some of Aldo's photographs do. Maybe, if the new airport X-ray machine doesn't vaporize my photos, so will mine.

A one-day class with Sessa runs from 9:00 a.m. to 5:00 p.m. and includes a stop for lunch. Sessa will give you a choice of itineraries and cameras. $1,000 PER PERSON, PRINTS EXTRA; FAX 54-11/4803-9071;