More than a hundred years ago, a secret lay dormant beneath the streets of San Telmo. No one saw it, no one imagined it. Until a 19th-century mansion opened its doors to the unexpected: tunnels, vaults, and brick passageways that seemed to emerge from a tale of mystery. Today it is known as El Zanjón de Granados, and visiting it is like stepping through a portal into the hidden past of Buenos Aires.

The adventure begins in the house’s courtyard, where the walls still whisper stories from long ago. Here, visitors learn how the residence changed through time: from an elegant family home to a crowded tenement, how it resisted epidemics that swept through the city, and how it was eventually restored to reveal its buried secrets. Each corner preserves traces of lives that once filled its spaces, and every object unearthed during restoration seems to tell a storey from another age.

Descending into the underground, the atmosphere transforms. The air becomes cooler, and every echo carries voices of forgotten times. Visitors walk through tunnels that once channelled the Granados stream, explore cisterns and wells that provided essential water, and encounter remnants that illustrate colonial daily life. Brick arches, stone walls, and preserved artefacts reveal how people lived, struggled, and adapted through centuries of change.

The play of light and shadow underground intensifies the mystery. Secrets of prosperity, floods, and legends intertwine, shaping a unique and almost theatrical setting. It feels as though history itself is alive, surrounding every step with stories waiting to be discovered.

By the end of the visit, one realises that El Zanjón de Granados is not merely a historical site or tourist attraction. It is a journey into the city’s hidden heart, a fantastic storey made real beneath San Telmo. Here, the boundaries between history and legend blur, inviting every visitor to walk alongside the mystery of Buenos Aires’ past.