Rome
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There is a reason why archaeologist Elsyria D’Ambrosio can barely contain her excitement as she passes through a dimly lit corridor beneath the Capitrine hill, once at the heart of ancient Rome.
“No one has seen these caves and tunnels in over a century,” D’Ambrosio tells CNN, plunging into the darkness. These rooms cover about 42,000 square feet, or 3,900 square meters (about three quarters of American soccer fields), but are located in the area below the ancient Roman forum and the 2,000-year-old Marcelo Theatre. At the deepest point, one of the caves extends approximately 985 feet below the surface.
Known as the Grottino Del Campidoglio, or the Caves of Capitoline, these tunnels were part of Roman fabric, even before the time of Julius Caesar, despite being forgotten in recent generations. Comprehensively developed in the Middle Ages, they housed the entire community, shops, taverns, restaurants, and in World War II, at various times until the 1920s, people refusing from the Alliance bombs.
On a sultry morning in July when CNN was granted exclusive access to the cave network, tourists sweated at temperatures of 95 degrees Fahrenheit (35 degrees Celsius) as they explored the Capitlin Square and Capitlin Museum complex designed by Michelangelo in the 16th century. In the cave, 75 feet below, the cave is clearly cool around 55F, with moist air causing sparkles on some of the tunnel surface.
Some parts are well constructed and lined with bricks, indicating development and use in the 19th century. Others are more loosely removed from tuff, Soft volcanic rocks that form the seven famous Roman hills. Walking through the tunnel is a trip back in time, as the complex layers of Rome’s history are exposed.
Today, almost a century later, nearly sealed under orders from Italian fascist dictator Benito Mussolini, the tunnels were lit, but pointing to the fact that scaffolding and other construction tools are no longer abandoned. In fact, work is underway to prepare a network for visitors. In late 2026 or early 2027, the tunnel will open as one of Rome’s latest historic tourist attractions.
For now, even the experts working to prepare them, entering the Grottino Del Campidoglio is still a journey of discovery. Despite many areas including the Imperial and Roman Forum and the nearby Colosseum, the tunnels have remained untouched, despite extensive renovations in recent years.
D’Ambrosio says the cave visitor experience is designed to combine archaeology and supereology, attracting different types of visitors from people focusing on better known sites on the ground. “This is an esoteric experience in many ways,” she adds. She has built a long career with sites like this, but D’Ambrosio manages the management aspects of this particular project, but says that her true love is tainted her hands.
There are still many things visitors will be amazed. As you stare at the blank reaching above a tunnel in one block-lined tunnel, you can see the white marble foundations of the Jupiter Temple, another Capitlin Hill treasure completed in the 6th century BC.
The underground complex served many purposes over the centuries. It first served as a stone quarry and then ultimately served as a former aquarium containing commercial structures and warehouses. In the 19th century, the caves were the economic epicenter of working-class communities who once lived in modest public housing built along the sides of the hill. German literature giant Johann Wolfgang von Goethe is said to have fallen in love with a woman who worked in one of the taverns and writes about his experiences in his travels, “The Trip in Italy.”
Little is known about when each of the underground caves had or when they had, but the etching by 18th-century Italian classical archaeologist and artist Giovanni Batista Pilanesi shows it as an active part of the city centre.
Mussolini tore through the housing and filled several tunnels with dirt to stabilize the hill above as part of his grand revitalization plan to modernize the Italian capital. During World War II, small sections were used as air raid shelters and were accompanied by heavy fortified doors. What you see in the tunnel is a variety of “gabinettes” or bathroom signs, as well as the number of streets.
Listen to archaeologist Elsiria D’Ambrosio about ancient tunnels under Rome
The work to open this underground world to visitors is completed in stages. Before clearing the caves and tunnels, archaeologists used laser scans to map remaining space and record marks during previous excavation operations. The photo and video exhibitions of the completed work will become part of the permanent display throughout the tunnel complex.
“The proposed intervention aims to protect the monument, on the one hand, through building restoration and safety, while on the other hand, will improve accessibility and ease of use, which is currently very limited.” “The Campidoglio Grottoes Project envisages conservative recovery and enhancement of underground passageways and cavities, running through the hills and crossing it in various directions and in multiple levels.”
Work to make it safe for tourists also includes managing radon gas naturally released from volcanic rocks that are disturbed during the restoration process. Workers are constantly tested for exposure levels and spending limited time in the cave. Antonio Colazzo, an archaeologist involved in the project, says that before the site is open to the public, specialized filters will be installed to scrub the air. “This will be managed by a forced ventilation system.”
Once the $2.8 million business is completed, museum space will be on the upper floors, but the entrance to the tunnel will be tightly controlled, and visitors will be led by guides to ensure the safety and integrity of the delicate structure. Invalid access will also be added. There are displays of ancient stone artifacts and various pots and vases buried in soil that are likely to be used by merchants for everything from olive oil to wine. Also visible are metal rings mounted on the wall. It is believed to have been used to connect animals placed in the cave complex.
The artifacts and materials recovered during previous excavations in the area and stored in the warehouses of the Capitlin Museum above were knocked down into the tunnel to be studied in the original context, says D’Ambrosia. “For archaeologists, everything is interesting,” she says. However, it is likely that visitors are interested in will remain there.
Even though all the work currently underway, there is little evidence from above that Capitlin Hill has an extensive network of caves and tunnels beneath it. But Ambrosio is sure they will soon become a major attraction for a city that is not short of shortage.
“The area has never been open to the public before,” says Ambrosio. “It was used by a population that is used as a warehouse, a store, or a tavern, but it’s never a place to visit.”
