Contractors Discover Forgotten Medieval Tunnel Beneath Welsh Garden

The passageway runs along a brook near Tintern Abbey, a 12th-century monastery on the border between Wales and England

View of the long-forgotten tunnel in Tintern, Wales
Researchers are still investigating who created the tunnel and why. Western Power Distribution

Electrical contractors in Tintern, a small Welsh village near the English border, have uncovered a clandestine network of medieval tunnels beneath a local resident’s garden.

As Nathan Bevan reports for Wales Online, employees from Western Power Distribution (WPD) spotted the secret passageway while attempting to move a wooden pole on a customer’s property.

“Before work began, all the usual checks and permissions were in place,” says team leader and WPD technician Allyn Gore in a statement. “… Nothing had shown up on any of our drawings or records to indicate there was anything unusual about the site.”

Per Wales Online, the workers stumbled onto the four-foot-tall corridor while digging up a footpath ahead of the installation of underground cables. They originally thought the opening was a cave but soon realized that it was manmade.

“I have been involved in other excavations where we have discovered old wells and cellars not shown on any plans,” says Gore in the statement, “but nothing as exciting and impressive as this.”

WPD officials partnered with Cadw, a government agency that protects Wales’ historic and cultural heritage, to halt the work, enabling researchers to more fully investigate the site.

As BBC News points out, the tunnel system does not appear on any known maps of the area, the oldest of which dates to the 18th century. And locals had no idea that the passageway existed.

Contractors Discover Forgotten Medieval Tunnel Beneath Welsh Garden
Tintern Abbey, a Gothic church referenced in a famed William Wordsworth poem, stands near the newly discovered tunnel. Saffron Blaze via Wikimedia Commons under CC BY-SA 3.0

Other medieval structures in the vicinity of the corridor could offer clues to its creation. Scholars are unsure exactly who made the tunnel and why, but WPD notes that it seems to follow the path of the Angiddy Brook and “may have been unknowingly walked on for centuries.”

Nearby Tintern Abbey is arguably the most significant historical site in the area. Established by Cistercian monks in 1131, the house of worship was expanded into a “masterpiece” of British Gothic architecture during the late 13th century but fell into disrepair following Henry VIII’s dissolution of Catholic monasteries in the late 1530s and ’40s, notes Cadw.

Today, the church’s ruins—which are filled with archaic furnaces, iron works and forges that may be linked to the tunnel—remain a major Welsh tourist attraction. (Fans of Romantic poet William Wordsworth may recognize the site’s name from his 1798 work “Lines Composed a Few Miles above Tintern Abbey.”)

This is far from the first time that archaeologists have identified forgotten passages beneath European cities.

The town of Oppenheim in western Germany, for instance, is home to an elaborate, 25-mile tunnel system that dates back to 700 A.D., as Jennifer Nalewicki wrote for Smithsonian magazine in 2016. People initially used the corridors to store food and wine; during the 17th century, workers in need of additional storage space expanded the labyrinthine network. Some locals even used the shafts to hide from Spanish forces during the Thirty Years’ War, which spanned 1618 to 1648.

Last year, meanwhile, excavations at a Danish train station unearthed a mysterious tunnel dated back to the 1800s, per the Copenhagen Post.

According to the South Wales Argus’ Dan Barnes, WPD technicians have resealed the newly discovered tunnel to prevent it from being damaged. The company plans to complete its electrical work in an alternative location nearby.