by Alessandra Ressa
Deep beneath the cobbled streets of Trieste, a labyrinth of ancient water networks has remained shrouded in mystery for centuries. But now, thanks to a dedicated group of volunteer speleologists, the city’s subterranean secrets are being revealed. This Saturday, October 19, a conference titled “The Hidden Waters of Trieste” will showcase the latest findings from the exploration of the Teresian Aqueduct, a remarkable feat of engineering dating back to the 18th century.
Held in the historic setting of Trieste’s Old Port, at the Luttazzi Hall in Warehouse 26, the event will bring together historians, researchers, and scientists to share new insights into the aqueduct, which has been largely forgotten and neglected until recently. The conference is expected to draw significant interest, especially following the recent discovery of a previously inaccessible section of the aqueduct, uncovered after nearly a century of being blocked by debris.
“The Teresian Aqueduct holds untold stories,” said Paolo Guglia, a historian and speleologist, who will open the event with an overview of the city’s vast underground water systems. “Each new exploration offers a window into Trieste’s past, while also presenting exciting possibilities for its future.”
The Adriatic Speleological Society, which has spearheaded efforts to restore and explore the aqueduct, will present unprecedented findings at the conference. Since 2018, the group has worked tirelessly to excavate and clear the tunnels that had been filled with water and sediment over the years. In 2022, their efforts made it possible to reopen long-forgotten sections of the aqueduct. This latest phase of exploration, however, has revealed a significant breakthrough.
“The Tschebull Gallery, a key part of the aqueduct, was inaccessible for over a hundred years,” said Marco Restaino, president of the Adriatic Speleological Society. “But after nearly a year of intense work, we’ve finally cleared a passage that has led to extraordinary new discoveries.”
For the first time, a video of the newly discovered section will be shown at the conference, offering a rare glimpse into this hidden world. The footage, produced by Raffaele Bruschi, captures the dramatic moment when explorers entered the previously sealed gallery, uncovering artifacts and engineering marvels that have not been seen in generations.
The Teresian Aqueduct, named after Empress Maria Theresa of Austria, was once a crucial water source for the city. Its vast underground network, which stretches for miles, has been a source of fascination for historians and speleologists alike. Yet, much of it has remained obscured, buried under layers of sediment and time. Now, as these tunnels are being rediscovered, experts believe they can contribute to a better understanding of Trieste’s industrial past and its complex relationship with water.
The upcoming conference will also feature zoologist Nicola Bressi from the Civic Museum of Natural History in Trieste, who will speak about the unique wildlife that inhabits the city’s underground spaces. Adelio Paladini will provide a deep dive into the technical archives of the Municipality of Trieste, offering insights into the city’s historic fountains and other hydraulic structures.
“The aqueduct is not just a marvel of engineering; it is a living part of the city’s ecosystem,” Bressi said. “Beneath the surface, life continues to thrive in ways that are both unexpected and fascinating.”
For the Adriatic Speleological Society, the discovery of the Tschebull Gallery is just the beginning. With over a kilometer of passages now cleared and accessible, there are hopes that the aqueduct could become a major site of historical and scientific interest. Volunteers have already outlined plans for further exploration and restoration, which they believe could help cement Trieste’s reputation as a city of hidden wonders.
The restoration of the aqueduct began in earnest in 2018, driven by the passion and perseverance of the society’s volunteer speleologists. After hundreds of expeditions, they have managed to reclaim large portions of the aqueduct’s network, which had been clogged with debris for decades. In 2023, they cleared a major blockage in the gallery, allowing access to the Tschebull Gallery for the first time in over a century.
“The underground of Trieste is a treasure trove, and we’ve only scratched the surface,” said Guglia. “With each discovery, we come closer to understanding the full scope of what lies beneath.”
Moderated by journalist and speleologist Alessandra Ressa, the conference promises to offer a deep dive—literally and figuratively—into one of Trieste’s most fascinating features. As the city looks ahead to the future, its hidden waters may hold the key to unlocking a rich, untold past.
The conference, which is open to the public, is part of a broader initiative by the Municipality of Trieste to promote the city’s cultural and historical heritage. It is set to run from 9:30 AM to 1:00 PM on October 19. Entrance is free, but seating is limited.
