Perhaps the most celebrated dive in all of Buenos Aires, Bar Plaza Dorrego has been pouring one icy-cold chopp (draught beer) after another for nigh on a century. The creaky old joint—with its checkered-tile floors, wooden tables gouged with graffiti, dusty bottles lining the walls, and ancient cash register—is the perfect perch for observing the doings of the Sunday-afternoon feria in Plaza Dorrego.

Living in a city with long, sweltering summer nights and no drinking laws, porteños should by rights be heavy drinkers. Far from it: Most young locals prefer to hug a single glass long into the night. Things were different in their grandparents' day, when first-generation immigrants from southern Europe favored a fortifying glass in the early evening. Eliot, a hip Palermo lounge bar and restaurant, places great store in B.A.'s venerable spirits, mixing old porteño classic labels—such as Legui, Hesperidina, and Pineral—with fruit to produce startling new creations. After sipping a couple, the full modern Argentine menu in the attached restaurant provides welcome fortification.

Opens Tuesdays through Sundays at 8:30 pm.

Housed in a former San Telmo general store dating back to 1798, El Viejo Almacén offers a vibrant example of how good—and surprisingly uncheesy—a full-on, traditional tango show can be. The venue was launched in the late '60s by the tango artist Edmundo Rivero, who has lovingly re-created the mood of an old-time milonga with a two-hour revue propelled by a classic orquestal (a tango ensemble that leans heavily on the bandoneón, or button accordian), four sets of bailarines (dancers) and a retinue of singers. The saucy spectacular is served up with a dinner that runs in the direction of empanadas, pasta, and steak.

The ultra-designed, ultracool Gran Bar Danzón's bistro menu showcases spiffy renditions of Argentine classics, but the real draw is the bar, with its 200-plus Argentine wines, expertly mixed cocktails (including the lavender-infused vodka concoction known as a Stacy Malibu), and well-heeled crowd, which tends to stick around until dawn on live-jazz nights.

This airy old-school café opposite the Recoleta Cemetery (be sure to check out the giant gomero, or rubber tree, out front) is a bona fide Buenos Aires classic. The city even designated La Biela—whose name refers to the connecting rod in an auto engine and whose walls are plastered with racing memorabilia—an official cultural landmark. Although it's mostly known as a place to spot local TV stars, grab a toasted ham-and-cheese sandwich, or peruse the paper over a café con leche, La Biela stays open until three in the morning, serving a variety of beer and spirits.

This all-purpose bar, café, and late-night discotheque offers a sophisticated take on the familiar cram-them-in-until-somebody-faints ethos of most B.A. nightclubs. At Tuesday night's Soirée Française, which ramps up with a soothing Francophilic soundtrack before shifting into electronica mode, the hip crowd drapes itself around the outsize aqua-blue bar for pastis cocktails and then floods the dance floor until all hours.

Closed Sundays.

A tiny emporium selling the best of Mendoza's small-batch Malbecs, Cabernets and Syrahs, La Finca (the name means "the farm") is a rustic nook outfitted with a smattering of tables for those who just can't wait to get home to have a nip. Tastings are accompanied by olives and other savory tapas.

Closed Sundays.

In operation for 70-odd years, Luna Park—with its landmark neon signage—has seen its share of history, from the 1935 funeral of tango legend Carlos Gardel to the chance encounter, in 1944, between Juan Perón and a certain señorita named Evita. The cavernous room—a former boxing arena—has also played host to the likes of Frank Sinatra, Luciano Pavarotti, Ray Charles, Oasis, and, more recently, the White Stripes.

Mansion Dandi Royal, the luxurious "Residential Tango Academy" housed in a 1903 San Telmo mansion, opens its Salon Dandi ballroom to the city's tangueros every Wednesday night for a milonga event called La Shusheta. The atmosphere of the relatively compact hall, with its bentwood chairs and neat corner bar, is refined yet cheery, a perfect place to watch (or join) the old pros, tourists, and acolytes of the Dandi's tango seminars, cutting loose with such steps as mordida (sandwich), gancho (hook), and ochos (figure eights).

Housed in a three-story mansion built in 1903 by the wealthy Allemand family, Milión encompasses three high-ceilinged dining rooms, two exterior terraces, and a warren of candlelit nooks. Beautiful porteños of all ages come to preen and flirt on the sweeping marble steps, or wander idly with a cocktail through a creeper-draped garden dominated by a towering loquat tree. The Allemands' piano, family portraits, marble fireplaces, and wall ornamentation remain intact, yet Milión is far from stuffy: Waiters are wont to wear T-shirts and dreadlocks, yet they display impeccable manners. An impressive cocktail list includes hard-to-find single malts Caol Ila and Glen Ord, making the first-floor bar popular with louche night owls, but the real attraction is standout cuisine: sweetbreads with salad and quail eggs, tuna steak dripping with lime, and a lamb tenderloin roasted with onions and wild rice.

The highlight of this Palermo Hollywood hot spot is the jam-packed Thursday dance party known as Club 69, B.A.'s essential night out since 1999. With a revolving cast of local and international DJs, Club 69 kicks it with funk, disco, and house; there's even an over-the-top stage show to keep things interesting. Friday night's Déjà Vu party runs more toward '80s New Wave, Goth, and vintage soft rock.

One of a smattering of B.A. hot spots known by number and not by name (Ocho7Ocho refers to the bar's street address), this diffusely lit, sofa-strewn speakeasy cultivates the air of a private club. Its unmarked doorway on a darkened block in up-and-coming Villa Crespo is just far enough from the cooler reaches of Palermo Viejo to dissuade all but the most determined nightspot habitués. It's worth a visit for the inventive cocktails alone, many mixed with Hesperidina, a B.A.-born spirit of quinine, gentian, and orange peel that's celebrated and lamented in equal measure for its powerful kick. The personable staff also takes great pride in 878's collection of hard-to-find single-malt Highland whiskies.

Open daily 8 pm to 2 am.

Owned by musician Fabián von Quintiero, SuperSoul (like Soul Café, its parent establishment next door) has a determinedly rock 'n' roll feel. The microscopic room is sweaty and loud, the decor runs to disco balls, and the overall effect is disarmingly fun. It's a perennial hot spot in bar-crawl-friendly Las Cañitas.

Closed Sundays.

In the mid-1850s, Buenos Aires was a modest settlement of 90,000 residents. A trickle of European newcomers drawn by open immigration and unlimited land soon became a flood. By 1914, the population had rocketed to 1.5 million. Squatting ten to a room in the tenements and shanties of poorer barrios such as La Boca, Pompeya, and Barracas, the immigrants poured their nostalgia and pent-up frustration verging on violence into the tango form. In its early days, the tango was practiced by same-sex couples in bordellos—by female prostitutes to kill time between tricks, by men to net the choicest girl. A century on, the dance is now respectably mainstream, but a glimmer of its darker roots can still be felt at one of the city's milongas, or open-floor tango dances, where experienced milongueros strut their stuff alongside beginners and aficionados. Unlike tourist-oriented tango shows, milongas tend to take place in brightly lit social clubs in far-away barrios. Music is played in tandas, or sets, divided by minute-long breaks reserved for the ritual choosing of partners for the next tanda. Invitations to dance, always made by men, are dispensed with when a man simply catches a woman's eye and gives a quick nod; to turn a man down, a woman should simply ignore the nod. Despite appearances, most people are there just to dance. Matinee dances are more suited to beginners.

El Niño Bien
1462 Humberto I
Constitución
Tel: 54 911 4147 8687

A haunt for genuine experts, El Niño Bien is held in a glorious Belle Époque ballroom in the deeply unfashionable Constitución district.

Club Gricel
1180 La Rioja
San Cristóbal
Tel: 54 11 4957 7157

Visitors can dance, learn, or just watch the exuberant color and passion when the experts get it right at this authentic milonga in run-down San Cristóbal.

Sunderland Club
3161 Lugones
Villa Urquiza
Tel: 54 11 4541 9776

Despite its uninspiring location on a basketball court in a neighborhood social center, the Sunderland Club boasts a 90-year history and immense credibility with genuine tangueros.

La Viruta
1366 Armenia
Palermo Viejo
Tel: 54 11 4774 6357

The venue, an Armenian social club, resembles a Ping-Pong hall, but La Viruta's location in Palermo Viejo and its eclectic mix of tango, swing, rock, and Argentine folk music has been pulling in the crowds for a decade. Dinner is available until 3 am; medialunas (croissants) are served at dawn.

Confitería Ideal
380 Suipacha
El Centro
Tel: 54 11 5265 8069
www.confiteriaideal.com

Confitería Ideal has been featured in most movies shot in Argentina, from Evita to The Tango Lesson. Matinee and evening milongas are held amid the building's decaying grandeur of marble stairways, mahogany paneling, and peeling plaster.

La Catedral
4006 Sarmiento
Abasto
Tel: 54 11 4932 8829

Located amid disused warehouses, La Catedral, held in a former granary, is delightfully shabby. Eccentric oil paintings and macabre sculptures adorn the walls, while young, louche dancers contend with chipped floorboards, all-pervading darkness, and dust clinging to every surface. Milongas are sometimes interspersed with poetry recitals or concerts.