You have to be very hard-hearted not to be seduced by the romantically crumbling facades and cobbled streets of San Telmo, a neighbourhood proud of its reputation as the guardian of the city’s traditions. A small, roughly square-shaped barrio, San Telmo is bounded to the north by Avenida Chile (six blocks south of Plaza de Mayo), to the west by Calle Piedras, to the east by Paseo Colón and to the south by Parque Lezama. Like neighbouring Monserrat, its main artery is Calle Defensa, once the main thoroughfare between the Plaza de Mayo and the city’s port.

The barrio’s appearance of decaying luxury is the result of a kind of reverse gentrification. When the city’s grand mansions were abandoned by their patrician owners after a yellow fever epidemic in 1871, they were soon converted into conventillos (tenements) by landlords keen to make a quick buck from newly arrived immigrants. This sudden loss of cachet preserved many of the barrio’s original features: whereas much of the north, centre and west of the city was variously torn down, smartened up or otherwise modernized, San Telmo’s inhabitants simply adapted the neighbourhood’s buildings to their needs. It’s still largely a working-class area, and well-heeled Palermo-dwellers may warn you off coming here, but the area’s superb architecture also attracts bohemians, students, backpackers and artists, from Argentina and abroad. Together with rising rents, the recent appearance of designer clothing and homewares stores among the traditional antiques shops is an indication that San Telmo may once again be going up in the world – though this latterday gentrification is not a development that everyone welcomes.

San Telmo is one of Buenos Aires’ major tourist attractions per se, particularly for its Sunday antiques market, the Feria de San Telmo, held in the neighbourhood’s central square, Plaza Dorrego; there’s usually a smaller version on Saturdays. It’s also the barrio most closely associated with tango, and the place where many of the best-known tango shows and bars have their home. At the southern end of the barrio, the small, palm-lined Parque Lezama, containing the city’s well-organized Museo Histórico Nacional, makes a restful spot to end a tour of the neighbourhood.