It’s not just a crack in the Roman pavement – a sinkhole has ripped open the pathway leading to one of the world’s oldest buildings. Archaeologists know they have to take advantage of any opportunity to inspect Rome’s underbelly. So, a team from the Agenzia Nazionale Stampa Associata (ANSA) descends into the ground, and they find a centuries-old relic of the historic city’s past.
The sinkhole in question appeared in front of the Pantheon, a house of worship that has been in continuous use since its 117 AD construction. The historic structure sits in Rome’s Piazza della Rotonda, where a 10-square-foot section of the earth collapsed into itself. Considering how many years of history the area has, it’s no wonder that archaeologists rushed to inspect the rubble.
Indeed, Rome has had its fair share of sinkholes appear across the city’s age-old landscape. Anywhere built above ancient quarries, catacombs or tunnels is susceptible to caving in after so long. And the Eternal City has lots of these cavities hidden beneath its cobblestone streets, especially in its eastern region, where workers once mined for rock.
Sometimes, a single year in Rome will see more than 100 sinkholes open up across the cityscape. Not all of them garner as much attention as the one that appeared in April 2020, though. The one right in front of the Pantheon was a call to arms to archaeologists, who explored the opening to find yet another piece of the city’s already incredible history.
The Pantheon stands today as the best-preserved of all of Rome’s ancient structures and, even more surprisingly, it remains in use. In fact, the age-old building fulfills nearly the same purpose as it had when constructed in 117 AD. It’s a church that closes to tourists on Saturdays and Sundays for Christian mass.
At the start of its history, though, the Pantheon didn’t serve a Christian congregation. The original structure, different from the one standing today, was built in approximately 25 B.C. Marcus Agrippa, whose father-in-law Augustus was Rome’s first emperor, constructed the first house of worship on the same site.
That version of the Pantheon had a much simpler footprint; it was rectangular in shape and had a gabled roof overhead. And it gave city dwellers a place to go and pray to the ancient Roman gods, not a Christian one. Indeed, the Greek words that build the name Pantheon indicate this: pan means “all,” and theos means “gods.”
The original Pantheon only stood for about 100 years before a fire ripped through the structure and destroyed it. Emperor Domitian – who reigned from 81 to 96 A.D. – had the temple rebuilt. But that one enjoyed even less longevity than its predecessor: it was struck by lightning and incinerated in 110.
At that point, the people who worshipped at the Pantheon began to worry. They believed that its destruction was a sign from their gods to say that they weren’t happy with the structure built in their honor. So, they left the post-lightning rubble of the Pantheon in place for eight years instead of rushing to rebuild something unsatisfactory.
Emperor Hadrian, who rose to power in 117, took it upon himself to try again. Indeed, the ruler had a deep appreciation for both architecture and art, and he made building new structures a focal point of his reign. Many of his ordered works still stand today; for instance, the 73-mile Hadrian’s Wall still stretches across northern England, where it once marked the northwestern border of his territory.
Most experts agree that construction on the third Pantheon finished between 126 and 128. When Hadrian cut the proverbial ribbon on the building, he added an inscription that honored its original founder – and confounded historians for years after the fact. It reads, “Marcus Agrippa the son of Lucius, three times Consul, made this.”
After digging though, experts now know that it was Hadrian who likely commissioned the current iteration of the Pantheon in the same spot as Agrippa’s first temple. What is unclear is how Hadrian used the structure after he rebuilt it, although there is evidence to show that he did sometimes play bost to his subjects within the church walls.
Two hundred years later, the Roman Empire moved its capital city from the Eternal City to Byzantium, known today as Istanbul. The move proved detrimental to the Pantheon, which declined into disrepair in the years following the shift. It continued to crumble until 609, when Pope Boniface IV stepped in.
At that time, Boniface IV requested permission from then-Byzantine emperor Phocas to give the Pantheon a new purpose. The Catholic figurehead hoped to convert the temple into a place for Christians to worship instead. His wish was granted, and he gave the structure a new name: Sancta Maria ad Martyres, Latin for St. Mary and the Martyrs.
With that, the Pantheon, a one-time pagan place of worship, became a Christian church. This marked the first time that such a swap had taken place. But it was a pivotal moment in the structure’s story, as the Pope had enough resources to restore the building to its former glory – and keep it that way.
And the Pantheon was certainly a structure worth safeguarding. Builders used a combination of concrete and bricks to build the impressive structure, which has three noteworthy sections. A portico with giant columns gives way to the rectangular interior. But it’s what’s overhead that has long impressed architects as a feat of engineering.
In fact, the Pantheon’s domed roof, which arcs overhead without the need for support, is still considered by some to be the ancient Romans’ greatest achievement in architecture. For more than 1,000 years, it stood as the largest cupola in the entire world and, to this day, it is the only concrete roof of its kind without any reinforcements to hold it up.
To get the concrete dome to stay this way for centuries required a perfect calculation on the part of the Pantheon’s architect, whose identity remains unknown. But the diameter of the cupola is exactly the same as the height of the Pantheon’s interior walls: 43.4 meters, or just over 142 feet.
The Pantheon’s final feat is the oculus at the center of its perfectly proportioned dome. The 28.5-foot circular opening in the middle of the cupola has long served a symbolic purpose, connecting worshippers to the gods above them. It also reduces the tension the dome places on its underlying structure, which has kept it standing strongly for so long.
The oculus does let rainwater into the Pantheon but, of course, the wise architect had a plan for this, too. Within the structure’s marble floors are barely visible drainage holes, which remove any precipitation to preserve the church. All of these ingenious architectural features, in addition to the beauty of the building itself, have made the Pantheon an inspiration to builders and designers for centuries.
Revered artist and sculptor Michelangelo supposedly said that the Pantheon was of divine design: men simply could not have created something so perfect. And President Thomas Jefferson looked to the cupola as inspiration for his historic home in Virginia, Monticello. Other American state capitol buildings have mimicked the one-time temple’s rounded roof, too.
And, because of its Catholic conversion and importance in the Roman landscape, the Pantheon became a noteworthy burial site for Renaissance luminaries, including the painter Raphael and Italian monarchs. Nowadays, tourists flock to visit the long-standing religious site, while locals attend its Saturday and Sunday masses, at which points the church is closed to external visitors.
With all of this history packed into the Pantheon, it makes sense why a sinkhole opening anywhere near the structure would be a big deal to archaeologists. It’s not uncommon for such openings to rip through the Roman landscape. Starting in 2009, the number of annual sinkholes in the city tripled from the long-time average of 30 per year.
Indeed, with thousands of years of human civilization in one place, a lot of Roman history has been buried as time has gone on. That includes its one-time network of quarries, which ancient miners created on the city’s eastern side. The sites of these age-old cavities, as well as tunnels and catacombs, are where sinkholes tend to appear today.
On top of that, the earth upon which Rome was built does the region no favors, either. A soft, sandy soil lays the foundation of the Eternal City. This, combined with all of the hidden holes, means a sinkhole can appear after a car or moped drives overhead, creating ground-shaking vibrations.
In April 2020 one such sinkhole appeared in front of the Pantheon.The 10-square-foot hole extended 8 feet into the ground. And that relatively tiny expanse of Roman real estate provided a glimpse into the city’s storied past. It took a team of archaeologists from ANSA to reveal a bit of ancient Roman history now sitting in plain sight.
When the archaeologists descended into the Pantheon-adjacent sinkhole, they pinpointed paving stones from the very early Rome’s days as the capital of an empire. The geological relics – seven travertine slabs in total – dated back to 25 to 27 B.C. The latter date is the same year of the empire’s foundation.
As previously mentioned, Agrippa built the first Pantheon around the same time, 25 B.C., and his father-in-law, Augustus, served as the Eternal City’s first emperor. As such, archaeologists knew that the travertine slabs were part of Agrippa’s work on the temple: he had designed the pavers himself, too.
After Agrippa’s Pantheon had burned down, Hadrian had a new temple built in its place, but the surrounding piazza was revamped. Further modifications took place at the start of the 200s, which pushed the original pavers further underground. It wasn’t the first time that this stonework had seen the light of day in modern times, though.
In the 1990s, workers laid a new network of service cables through an underground tunnel. At this time, they first laid their eyes on the travertine stonework. But the sinkhole re-revealed the more-than-2,000-year-old tiles when the overhead cobblestones fell into the very service tunnel built 20 years ago.
When the ancient travertine tiles first came to light in the 1990s, they were re-buried, but with a layer of pozzolan on top. Rome’s special superintendent Daniela Porro explained in a statement that the material behaves very similarly to cement when wet, thus protecting the stones from damage over the decades.
Porro highlighted the vital role that polozzan had played in the re-discovery of the ancient travertine. She said in her May 2020 statement that it was “an unequivocal demonstration of how important archaeological protection is, not only an opportunity for knowledge but fundamental for the preservation of the testimonies of our history, an invaluable heritage in particular in a city like Rome.”
For all of their planning and preservatory tactics, though, Roman officials simply got lucky with the time that the Pantheon’s sinkhole had opened up. La Stampa, a national Italian newspaper, reported, “The area, fortunately closed, could have become a really dangerous trap for Romans and the thousands of tourists who on a beautiful day in the middle of spring, in a ‘normal’ period, would have filled it.”
Luckily, though, Rome’s leadership has plans to protect the historic city from the sinkholes that keep opening up beneath their feet. In March 2018 the city announced its plan to fix the city’s 50,000 potholes. Mayor Virginia Raggi designated a €17 million budget for filling in these dangerous openings in the city’s streets.
When Raggi shared the plan, she promised that the city would fix 50,000 potholes in the first month of the program. However, as of the spring of 2020, the effort to fill in Roman potholes has proved slow going. And partly for this reason, sinkholes continue to collapse across the Italian capital.
Indeed, the Pantheon-adjacent sinkhole hasn’t been the only one to appear near one of Rome’s iconic historical sites. In January 2020 a crater opened up on Via Marco Aurelio, which runs very close to the Colosseum. City officials evacuated an entire apartment building as they inspected the integrity of the ground surrounding the new cavity.
And, since the Pantheon sinkhole opened up, archaeologists have uncovered even more ancient Roman treasures. At the end of May 2020, a team assembled in Verona uncovered an astonishing relic of the country’s empirical past. Experts before them had discovered the remains of a third-century villa in the hills outside Verona, a northern Italian city.
However, archaeologists knew that there was more to the villa than the remnants uncovered in 1922. So, they returned nearly 100 years later to dig in October 2019 and February 2020. Neither of those excavations yielded anything, but a May 2020 dig revealed an invaluable treasure: an ancient mosaic floor that had somehow stayed perfectly preserved for centuries.
Authorities from the town of Negrar di Valpolicella shared details of the find through their Facebook page. They announced, “After countless decades of failed attempts, part of the floor and foundations of the Roman villa located north of Verona, discovered by scholars a century ago, has finally been brought to light.”
The fate of the Pantheon’s sinkhole-exposed street tiles remains to be seen, but Negrar di Valpolicella’s officials hoped the mosaic floor would eventually be shared and enjoyed by visitors. Mayor Roberto Grison told the local newspaper L’Arena, “We believe a cultural site of this value deserves attention and should be enhanced.” Perhaps the same belief will bring the Pantheon’s 2,000-year-old travertine to light permanently.