Nearly 2,000 years after a devastating volcanic eruption destroyed and entombed a thriving Roman city, researchers are turning to the novel technique of digital archaeology to reveal the "lost Pompeii."
Mount Vesuvius erupted in AD 79, covering Pompeii in a thick layer of molten rock, ash and debris. Some residents fled, while others were killed, trapped by volcanic material. The ghostly ruins, frozen in time, became a tableau that archaeologists have investigated since 1748.
Excavations have revealed the buildings and artifacts hidden beneath the ash, colorful remains of decorative frescoes, and haunting remains of the city's residents.
But not all of the architectural structures were preserved in Pompeii, leaving researchers with lingering questions about daily life in the ancient, southern Italian city.
Now, a sophisticated combination of remote sensing technology, close-range photography and good old-fashioned archaeological techniques are helping researchers pick out once-hidden clues, revealing aspects of Pompeii that have been lost over time -- such as towers, symbols of wealth and power, that might have once shaped the cityscape.
"By reconstructing the lost architecture, we gain a more nuanced and historically accurate understanding of the ancient city and life within it," said co-lead study author Dr. Susanne Muth, professor at Humboldt University of Berlin's Institute for Archaeology.
The findings and digital recreations, made by the Pompeii Reset project and published recently in the E-Journal of the Excavations of Pompeii, could even change the way we envision ancient Pompeii's skyline.
Life among Pompeii's ruins
During a visit to Pompeii with students in 2022, Muth became inspired by the Archaeological Park of Pompeii's efforts to preserve the city. Aware of the challenges of studying fragile ruins amid fluctuating weather and a changing climate, she proposed an idea to preserve Pompeii's cultural heritage through noninvasive digital reconstruction while gaining knowledge about the ancient city.
The Archaeological Park of Pompeii took an interest and teamed up with Humboldt University, which has an archaeology department with a strong digital focus that includes past projects such as a digital reconstruction of the ancient Roman Forum.
As part of the ongoing work, the project team employs techniques such as LiDAR (light detection and ranging) scans and photography to document what remains of Pompeii's buildings and create 3D models. Then, the researchers use clues revealed by the scans -- such as holes that show evidence of missing structures -- to make digital reconstructions of how the structures may have appeared before the eruption.
Other recent explorations of Pompeii's people and architecture also revealed that inhabitants returned to the ruins a few decades after the disaster in in AD 79.
Researchers used drones to scan the Pompeiian building. Mount Vesuvius can be seen in the background.
Susanne Muth/Dirk Mariaschk/Elis Ruhemann/Pompeii Reset Project/Humboldt University of Berlin
"The volcanic debris and ash covering Pompeii after the eruption reached approximately five meters height," or 16 feet, said co-lead study author Gabriel Zuchtriegel, the archaeological park's director, via email, adding that "you could still see the upper floors emerging from the ash, in a sort of grey desert."
Former ground floors became cellars where inhabitants built ovens, mills and fireplaces, which were uncovered earlier this year. However, those later Pompeii residents ultimately abandoned the site following another devastating eruption in the fifth century, Zuchtriegel said.
When excavations first began in the mid-1700s, everything beneath the ash layer was still preserved -- but the top floors had decayed and disappeared.
There was a lack of interest in those missing top floors, as they were thought to be simple living quarters for Pompeii's slaves and poorer citizens, Muth said. "For many centuries, excavations in Pompeii focused more on finding precious statues and wall paintings," she noted.
But renewed interest came from a desire to understand the everyday lives of ordinary citizens, she added. "In the process, it has been discovered that the wealthier citizens of Pompeii also used rooms on the upper floors, as traces of richer furnishings have been found there."
As the researchers focused their search on the upper floors, they were drawn to a newly excavated residence: the Casa del Tiaso, or the House of the Thiasos.
In one ground floor room stood a monumental stone staircase that led to a second floor. Indentations on the walls near the top of the staircase pointed to possible evidence that a second staircase made from wood had existed on the missing upper floor and led even higher to a third floor.
"When we began to reconstruct this room in terms of its lost architecture, it became clear to us that it could only be a tower," Muth said.
A digital reconstruction shows a tower that might have existed in a luxury home of ancient Pompeii.
Susanne Muth/Dirk Mariaschk/Elis Ruhemann/Pompeii Reset Project/Humboldt University of Berlin
A luxury home in a lost city
The Casa del Tiaso was one of Pompeii's most lavish homes and probably belonged to an influential family, Zuchtriegel said.
It contained large decorative banquet rooms, with one opening up into a garden courtyard and another leading to a private thermal bath complex, Muth noted.
A digital rendering depicts one of the lavish rooms that has been excavated in the Casa del Tiaso.
Susanne Muth/Dirk Mariaschk/Elis Ruhemann/Pompeii Reset Project/Humboldt University of Berlin
At the time, large country villas outside the city walls included towers that were used for hosting banquets and showcasing grand views.
Roman writer Pliny the Younger described such a tower in his country villa where he could enjoy the sunrise and sunset, Muth said. Legend has it that Roman emperor Nero observed the burning of Rome from a tower in the Gardens of Maecenas. Ancient texts from the second century BC and paintings from the first century BC to the first century AD, too, include towers attached to luxurious villas.
But archaeologists haven't looked for evidence of towers within Roman cities such as Pompeii for a good reason: These houses were often built as sprawling structures, rather than tightly clustered multiple-floor dwellings, Muth said.
"The unique findings in the Casa del Tiaso now lead us to believe that such towers also existed in cities as an element of wealthy residential architecture that sought to imitate the magnificent villa architecture and with which the homeowner wanted to represent his social status from afar," Muth said.
The owner of the Casa del Tiaso may have hosted banquets with guests on the upper floor of the tower, enjoying the view of the city and the Gulf of Naples, she added.
The tower may have also been used to observe stars in the night sky. Astrology was popular in Roman society, although several emperors tried to forbid it, Zuchtriegel noted.
Religious regulations may explain why towers were not common in the city, said Dr. Marcello Mogetta, chair of the department of classics, archaeology and religion at the University of Missouri. Mogetta was not involved in the new research.
In ancient Rome, temples and sanctuaries needed clear sight lines for the taking of auspices -- interpreting omens from the behavior of birds -- and other rituals. Taller private buildings were restricted, leading urban mansions to expand downward to create sunken floors, Mogetta said.
While there is clear evidence of upper floor apartments in Pompeii, a high-rise tower in a prestigious home like the House of Thiasos is unprecedented but not far-fetched, he said.
Scans and excavations were used to create a digital twin of the existing structure.
Susanne Muth/Dirk Mariaschk/Elis Ruhemann/Pompeii Reset Project/Humboldt University of Berlin
Towers also speak to creative innovation employed by Pompeii residents seeking to assert prestige, Mogetta added.
"Tower-like structures do appear in Pompeian wall paintings representing urban landscapes, though these have traditionally been dismissed as artistic fantasy driven by the taste for illusionism," Mogetta said. "The proposed reconstruction challenges that assumption. If accurate, it means those painted scenes may have reflected the real cityscape more closely than we thought."
Reconstructing the past
Digitally reconstructing Pompeii's buildings is like detective work, Muth said. All evidence is meticulously gathered, and no detail is left undocumented.
Researchers are now using drones to capture scans of entire buildings, laser technology to measure surfaces and close-range photography to determine textural details. Overlapping images help to create 3D models in a process called photogrammetry.
A digital twin of a building is made from the scans and photos, which researchers use to reconstruct the lost architecture, virtually reinserting wooden beams into holes in the wall and following patterns to determine where upper floors or stairs once existed.
The researchers proposed this rendering as tested possibility for a missing wooden floor that might have existed near the top of the stone staircase.
Susanne Muth/Dirk Mariaschk/Elis Ruhemann/Pompeii Reset Project/Humboldt University of Berlin
"We proceed very cautiously, discuss a lot, test a proposal, reject it again, correct it, discover new clues, compare these clues with other buildings in Pompeii to find analogies," Muth said. "Step by step, a 3D model emerges on which we can transparently develop our arguments and proposals and then present them so that they can be reviewed and discussed by the scientific community."
Archaeologists have long employed drawings or scaled-down 3D models to reconstruct lost architecture. Digital archaeology takes the process a few steps further, Muth said.
It's easy for two-dimensional drawings to contain errors because they can only be checked from one angle. But 3D models must be 100% accurate from every angle.
"Only when the building's structural design is precisely recreated digitally in a 3D model can the architecture be understood and a plausible reconstruction developed," Muth said.
Computer game technology is also making 3D models more accessible, allowing for a closer examination of ancient living spaces by creating virtual walk-throughs.
"We can more concretely visualize a banquet by candlelight, or a celebration at the top of the tower of the Casa del Tiaso, but also the oppressive working conditions in the so-called slave bakery next door," Muth explained. "All this will help us to ask and obtain new questions and new answers about life in Pompeii."
Still, questions linger about whether there were more houses in Pompeii that once included towers, and the team continues to search for traces of lost upper floors.
"For those who could not take advantage of natural vistas, a tower-like structure was a clever solution -- combining spectacle, visibility, and social signaling in one architectural gesture," Mogetta said. "More work by the Pompei Reset project in other sectors of town is needed to reveal how widespread the phenomenon really was."
Ancient homes rarely survive the passage of time, especially millennia, and if they do, only fragments like sturdy foundations remain to mark where a residence once stood. But some sites, such as Pompeii, are exceptional and could be used to reconstruct ancient skylines and show how cities grew over time. For instance, researchers know medieval Italy was filled with towers because some of them still stand today.
At the archaeological site of Çatalhöyük , there is evidence of a network of homes built so closely together that Neolithic people living there between 7400 BC and 5200 BC had to use the roofs to access their interiors. Over time, new dwellings were built on top of the original homes.
"We know that cities and settlements in the past must often have had a taller skyline than we now have direct access to, from Neolithic Çatalhöyük to the cities of medieval Italy, and the Roman world is no exception," said Daniel Diffendale, a postdoctoral researcher at the Scuola Normale Superiore in Pisa, Italy, who was not involved in the new work. "There is evidence of taller buildings if you look for it."
The researchers hypothesize how the existing beam holes may have been used to support a tower atop the the house.
Susanne Muth/Dirk Mariaschk/Elis Ruhemann/Pompeii Reset Project/Humboldt University of Berlin
Preserving Pompeii for the future
Muth's goal is for the digital reconstruction of the Casa del Tiaso eventually to include every room. But the wider project has no end date; the team wants to see how many buildings it can virtually reconstruct to preserve Pompeii's heritage.
Digital tools have become a fundamental way to monitor the state of Pompeii's conservation and determine where intervention is needed.
They can also create models of parts of the city that weren't preserved at all, Zuchtriegel said.
"Digital archaeology is much more than simply creating fanciful reconstructions of ancient buildings," he said. "It's a way of thinking through these structures and how they really worked and were used."
More than 13,000 rooms have been excavated in the lost city since 1748, with one-third of ancient Pompeii remaining buried under volcanic ash.
Insights from recent excavations could inform how researchers understand houses that were first investigated decades or centuries ago, but excavating all of Pompeii isn't the goal, Zuchtriegel said. The archaeological park wants to leave something for future generations.
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