Buenos Aires used to run on nostalgia and was proud to consider itself more European than Latin. Then came the financial collapse of 2001 and everything changed overnight. David Ebershoff visits the new Buenos Aires, an electrifying—and deeply affordable—city, where necessity really is the mother of invention

It used to be that if you were visiting Buenos Aires, especially for a short stay, you had little reason to stray beyond the neighborhoods in and around the Microcentro, an orderly European grid of narrow streets and wider avenues that is home to many government offices and historic churches. Or perhaps you'd branch out to nearby Recoleta, the elegant enclave of early-twentieth-century embassies, neoclassical mansions, doorman apartment buildings, a cemetery for the elite, and a central avenue lined with upscale boutiques: Armani, Ralph Lauren, Vuitton.

Your visit would probably begin at the Plaza de Mayo, a paved oval cut with paths, palms, and patches of grass, an obelisk standing nobly at the center. At one end of the plaza is the Casa Rosada, the faded pink presidential palace from whose balcony Eva Perón cried for Argentina. This is a city of pronouncements and protests, and the Plaza de Mayo has been the site of military coups and political rallies and gatherings throughout the country's history. Here the crowds thronged for a look at Evita. Here the Madres de Plaza de Mayo, a group of mothers demanding a full inquiry into the disappearance of their sons and daughters—an estimated thirty thousand of whom, political opponents of the government, vanished between 1976 and 1983—first began congregating in 1977 (every Thursday at 3:30 p.m., the group assembles in the plaza still). And here, more recently, is where demonstrators lit bonfires to decry the government's handling of the December 2001 economic crisis, the event that was the catalyst for much of the city's recent transformation.

But I'm getting ahead of myself. Let's continue. Here, on the northwest corner of the plaza, is the Catedral Metropolitana. Completed in 1827, it resembles a Greek temple from the outside, with twelve massive fluted columns defending the entrance. Once inside you could believe, however, as in many places in the Microcentro, that you'd been transported to Catholic Europe. The floor plan is in the shape of a Latin cross, and everywhere are tons and tons of marble the color of weak tea. In a side chapel, you'd visit the flag-draped tomb of General José de San Martín, who liberated Argentina from more than two centuries of Spanish rule in 1816, and where two military guards, stiff and still in full regalia—gold braid and red epaulets—stand with drawn swords. If you were the goofy type, you might try to get one of the soldiers to crack a smile. (I did, and was rewarded with a smirk.)

In the afternoon, you'd drop by the Basílica de San Francisco. This Baroque church and convent, which dates from 1754, is one of the oldest in the city, its twin bell towers, topped by copper cupolas, floating over the nearby rooftops. Here is the gift shop selling postcards, rosary beads, sacks of hard candy, and soaps and salves made on a bee farm outside the city by four Franciscan monks. There are white jars containing a beeswax-and-pollen cream for the skin around the eyes, brown jars holding something for rough elbows that looks like chocolate pudding. The man behind the counter would give you a lozenge of honey-flavored candy wrapped in cellophane. Next you'd go for a café con leche and a sugary alfajor, a smear of dulce de leche sandwiched between two shortbread cookies, at La Puerto Rico, the kind of old-fashioned place with a long wooden bar, pastries and croissants displayed behind glass, a terrazzo floor, and waiters in crisp white aprons who hold their coffeepots three feet above your cup, tip, and pour without splashing a drop. If you were in town on a Saturday night, you might return here for the dinner-and-tango show and marvel as a man with a naughty mustache and a woman with glossy hair prowl, strut, and tangle like two black cats. And so this was the visit you'd have, this kind of dreamy, nostalgic stroll through the city's past—the kind that has charmed visitors for decades, and deservedly so.