Boca Juniors had wandered for years - the old port, Isla Demarchi, a wooden-stand ground on Brandsen street - before committing to this cramped corner. In 1931, the club's leadership bought the land from the city. The job of designing the stadium went to the firm of Delpini, Sulčič, and Bes, the same office behind the great Mercado de Abasto market. The problem was geometry: residential buildings pressed right up against one edge, leaving no room to extend a fourth grandstand outward. The solution gave the stadium its silhouette and its name. With nowhere to go but up, the stands rose at a near-vertical pitch, and that severe, half-open form reminded people of a bombonera - a chocolate box. The nickname stuck, especially after the third tier was finished in 1953.

The new stadium opened on May 25, 1940, with a friendly against San Lorenzo. There were no floodlights yet, so the match was cut short - two halves of just thirty-five minutes, played before the light failed. Boca won 2-0, both goals scored by Ricardo Alarcón. Eight days later, on June 2, Alarcón scored again as Boca beat Newell's Old Boys in the first official fixture. The expansions came steadily after that: a second tier in 1941, the famous third tier and lighting completed in 1953, a press wing and museum and a partial fourth side added under president Mauricio Macri in 1996. The stadium that began as a 70-minute experiment now holds well over fifty thousand.

Inside and out, the concrete is alive with painting. The artist Pérez Celis covered the walls with murals of the club's legends and of the barrio itself - dockworkers, immigrant families, the Italian laborers who built this part of the city. A vast tiled mural in blue and yellow honors Diego Maradona, who supported Boca, played for Boca, and kept his own box in the ground. The museum beneath the grandstands traces the club from its founding in 1905. Outside stand bronze statues: Maradona; Martín Palermo, the all-time top scorer; Román Riquelme; and the coach Carlos Bianchi, whose teams once went forty matches unbeaten. From the highest rows, on a clear day, you can see past the rim to the dockyards and the river beyond.

The supporters of Boca are nicknamed La Doce - "the Twelfth," the player the eleven on the field cannot see but always feel. The atmosphere here is regularly named among the most intense in football, never more so than during the Superclásico against River Plate, when tickets become nearly impossible to find. The stadium has carried two presidents' names - first Camilo Cichero in 1986, then Alberto J. Armando in 2000 - yet almost no one uses either. To the city and the world it remains simply La Bombonera, and even Hollywood and arthouse cinema have come to film inside its strange, steep walls. The Argentine national team built much of its early home record here before larger venues took over: across twenty-seven matches it lost only twice.