El Zanjón de Granados

A journey to the origins of Buenos Aires

Hidden beneath Defensa street, in the heart of San Telmo, El Zanjón de Granados is the most important archaeological site in the City of Buenos Aires. Beneath a stately 19th-century mansion stretches a network of tunnels and colonial ruins connecting the poetry, history, and architecture of four centuries of porteño life.

History

Since the city’s first founding by Pedro de Mendoza in 1536, the land where El Zanjón now stands formed part of the southern boundary of the Spanish settlement. The underground stream that gave the site its name — the Zanjón de Granados — was enclosed in pipes in 1787 to drain flooding and, in 1892, permanently buried with the arrival of the modern sewage system.

During the 19th century, the mansion known as Los Patios housed families from the porteño elite until the yellow fever epidemic of the 1880s drove the wealthy northward. The building then became a conventillo for immigrants, before falling into complete abandonment in the 1970s.

In 1985, chemist Jorge Eckstein discovered, almost by chance, the hidden tunnels beneath the ruins. Over 38 years he dedicated his life to restoring the complex — Los Patios, the Casa Mínima, and El Puente — creating what he called an exercise in “reconciliation” between the past, the present, and the future.

The visit

Guided tours take visitors through the mansion’s restored courtyards and descend into the underground tunnels, where traces of different eras coexist: from colonial Buenos Aires to the conventillo of the early 20th century. The site also offers special activities such as El Zanjón Ilustrado para Niños y Familias and private events in its unique spaces.

Address: Defensa 755, San Telmo (1065), Buenos Aires
Hours: Every day from 11 a.m. to 5 p.m.
Contact: turismo@elzanjon.com.ar — +54 11 7078-1542 (weekdays)