Between 1880 and 1930, Buenos Aires rebuilt itself as a European capital. The grand Avenida de Mayo, completed in 1894, connected the Casa Rosada to the Congress building in a conscious imitation of Parisian boulevards. The Teatro Colon, opened in 1908, was designed to rival the opera houses of Europe and succeeded - its acoustics remain among the world's finest. The neighborhoods of Recoleta and Palermo filled with French mansions and Italian palazzos built by families enriched by beef exports.

The transformation was deliberate. Argentina's leaders wanted to replace the colonial Spanish city with something that announced arrival in the modern world. They hired European architects, imported European materials, and encouraged European immigration to populate their European city. By 1914, half of Buenos Aires' population was foreign-born. The Italian influence remains in the accent - Rioplatense Spanish borrows heavily from Italian intonation - and in neighborhoods like La Boca, where sheet-metal houses are painted in the bright colors that immigrants brought from Genoa. The grandeur they built remains, though maintained imperfectly; the Belle Epoque buildings crack and fade while the city lacks funds for restoration.

Tango emerged in the 1880s from the conventillos - the tenement houses of La Boca and San Telmo where immigrants crammed together in poverty. The music blended African rhythms brought by descendants of slaves, Italian melodies, Spanish guitar, and something harder to trace - the longing of people far from home, the melancholy of lives that did not match expectations. The dance was intimate, sometimes scandalous; respectable society rejected it until Paris embraced it in the 1910s, and then Buenos Aires claimed it as national treasure.

The golden age of tango ran from the 1930s to the 1950s, when Carlos Gardel became a legend and orchestras filled the dance halls of downtown Buenos Aires. Military governments suppressed it; the dictatorship of 1976-1983 viewed tango gatherings with suspicion. The revival began in the 1990s, fueled by tourism and nostalgia. Now milongas - tango dance halls - operate nightly across the city, mixing locals and visitors, serious dancers and beginners, preserving a form that remains somehow vital even as it becomes heritage. Tango is melancholy set to music; Buenos Aires is a city that suits melancholy.

Between 1976 and 1983, Argentina's military dictatorship 'disappeared' an estimated 30,000 people - students, workers, journalists, priests, anyone suspected of leftist sympathies. The victims were taken from homes and workplaces, held in clandestine detention centers, tortured, and killed; most bodies were never recovered. The ESMA - the Naval Mechanics School in Buenos Aires - held 5,000 prisoners; fewer than 200 survived.

The Mothers of the Plaza de Mayo began marching in 1977, walking silently around the plaza in front of the Casa Rosada every Thursday afternoon, wearing white headscarves, carrying photographs of their missing children. The dictatorship called them 'las locas' - the crazy women - but they persisted through threats and the disappearance of their own members. They still march, though most original mothers have died; the Thursday protests continue as memorial and warning. The dictatorship ended in 1983, the trials eventually held, the ESMA converted to a Museum of Memory. But the wounds remain open - trials continue, grandchildren stolen from murdered parents are still being identified through DNA. Buenos Aires carries this history in its streets.

In December 2001, Argentina defaulted on $100 billion in debt, the largest sovereign default in history at that time. The peso, pegged to the dollar, collapsed; the middle class saw savings wiped out overnight. Riots brought down four presidents in two weeks. The economy contracted 11% in 2002; poverty rates doubled. Argentines who had considered themselves part of the developed world found themselves queuing at soup kitchens.

Buenos Aires adapted as it always has. Barter networks emerged when currency became worthless. Factories abandoned by owners were occupied by workers and resumed production. The crisis passed - Argentina restructured its debt, the economy recovered, the commodity boom of the 2000s brought new prosperity. But another crisis hit in 2018, another IMF bailout, another devaluation. The cycles seem built into Argentine DNA: boom followed by bust followed by recovery followed by another boom. Portenos - as Buenos Aires residents call themselves - have learned to expect crisis and survive it. The cafes stay open, the tango halls fill, the Sunday markets spread through San Telmo. Life continues despite economics.

The extremes of Buenos Aires are visible in two neighborhoods twenty minutes apart. Recoleta was farmland until yellow fever drove the wealthy north from San Telmo in the 1870s; they built mansions and filled the Recoleta Cemetery with mausoleums rivaling small churches. Eva Peron is buried here, her tomb perpetually covered in flowers. The museums and parks and cafes of Recoleta serve a population that considers itself European, sophisticated, separate from the chaos of lesser Latin American capitals.

La Boca, where the Riachuelo meets the Rio de la Plata, was home to port workers and immigrants. The sheet-metal houses painted in bright colors - originally using leftover ship paint - now serve as tourist backdrop, though the neighborhood beyond the famous Caminito street remains working-class and occasionally dangerous. The football club Boca Juniors, whose stadium La Bombonera shakes when fans jump in unison, represents the neighborhood's identity: tough, passionate, proudly plebeian. Buenos Aires contains both Recoletas and both Bocas, the city of grand avenues and the city of corrugated iron, each defining itself against the other.