With the massive immigration to Argentina in the late 1800s, different ethnic groups tended to congregate in specific neighborhods. Here’s a sample of generally who lived where in 1880 Buenos Aires: Italians favored La Boca; Spaniards were found in Monserrat, San Cristóbal, San Nicolás, and Constitución; the Syrians and Lebanese congregated around Retiro; Jews and Russians in Once. (Source).