Historical mysteries solved by science in 2025

By Ashley Strickland, CNN

(CNN) — Researchers across the globe put on their sleuthing hats this year to provide answers to questions that have lingered from decades to centuries. The thought-provoking findings offer new ways of understanding the past.

Archaeological exploration of historic sites yielded fresh insights. An analysis of a quarry containing unfinished statues showed how wayfaring Polynesians created the massive stone heads found across Rapa Nui, or Easter Island.

Meanwhile, a new project exploring Pompeii uncovered a stone staircase that could reconstruct what the ancient Roman city’s skyline once looked like before a volcanic eruption in AD 79 entombed it in a thick layer of ash.

A combination of microbotanical analysis and sweeping aerial drone footage has also enabled researchers to arrive at a new hypothesis about who created the mysterious “band of holes” formation, a series of about 5,200 holes dotting the Peruvian Andes.

Some research leads to more questions than answers, such as the inventive ways scholars have tried to determine how celebrated author Jane Austen died by analyzing her own words in the absence of medical documents.

Here are some of the most memorable findings in 2025 that provided answers to long-standing historical mysteries.

A mysterious mummy

A water leak in a crypt containing the “air-dried chaplain” helped reveal the identity of an unusually well-preserved body kept in a remote Austrian village church since the 1700s.

With intact skin and tissue, the mummified body, thought to be an 18th century clergyman, had drawn speculation of healing properties and even rumors of being poisoned.

Renovations to repair the water damage prompted the body’s removal, creating an opportunity to perform CT scans, analysis of bone and tissue samples, and radiocarbon dating. Researchers determined the remains belonged to Franz Xaver Sidler von Rosenegg, an aristocrat who was a monk before becoming the parish vicar at St. Thomas am Blasenstein.

The team not only found that a previously undocumented embalming method was responsible for the cleric’s air-dried state, but also proposed a new hypothesis for his death and solved the mystery of a glass object found inside his remains.

The boat from nowhere

The Hjortspring boat, on display at the National Museum of Denmark in Copenhagen, has long been a vessel of mysterious origin.

Archaeologists first excavated the wooden ship from a bog on the Danish island of Als in the 1920s, more than 2,000 years after it sank. The boat was laden with weapons, suggesting it carried warriors with intent to attack the island.

No clues as to where the boat originated or who it carried existed — until now.

A new analysis of the ship’s materials suggest it traveled much farther than previously thought, meaning the attack likely was premeditated. And a partial human fingerprint found in tar residue could provide a direct link to one of the ship’s crew.

“Fingerprints are very rare for this time period and area,” said lead study author Mikael Fauvelle, an associate professor and researcher in the department of archaeology and ancient history at Lund University in Sweden, adding that “to find one on such a unique boat is extremely special.”

Speaking of historic ships, another fresh analysis has shown that polar explorer Ernest Shackleton’s vessel, the HMS Endurance, wasn’t doomed by its broken rudder. Instead, the ship sank in 1915 due to structural weaknesses — and Shackleton knew about them before chasing his polar dream anyway.

Ice age mistaken identity

More than 14,000 years ago, a den collapsed around two female pups in northern Siberia, trapping them. The mummified remains of the “Tumat Puppies,” thought to be sisters, were unearthed separately in 2011 and 2015.

The pups were so well-preserved that they are still covered in fur and hints of a last meal remain in their stomachs. Researchers thought they might be early domesticated dogs or tamed wolves that lived near humans.

But a new study analyzing genetic data and chemical signatures suggests the Tumat Puppies were wolf cubs that didn’t interact with humans at all.

The research is shedding light on the complexities around determining when dogs were domesticated and began living alongside humans.

An ill-fated army

When Napoleon Bonaparte invaded Russia in 1812, the French emperor led an army of over half a million men.

Six months later, a fraction of his soldiers — an estimated tens of thousands — returned to France after a forced retreat. While a combination of battle, starvation, cold and a typhus epidemic were considered factors in the costly, tragic loss of hundreds of thousands of men, genetic evidence has suggested newfound culprits.

“Previously, we just thought that there was one infectious disease that decimated the Napoleon army — the typhus,” said lead study author Rémi Barbieri, a postdoctoral researcher at Estonia’s University of Tartu.

Barbieri’s team discovered previously undetected pathogens Salmonella enterica and Borrelia recurrentis in the teeth of fallen soldiers. The bacteria cause paratyphoid fever and relapsing fever, respectively, which could have contributed to the soldiers’ deaths.

Honorable mentions

This year, scientists also delivered answers to these baffling questions:

— Researchers finally identified the mystery volcano that unleashed an eruption so violent that it cooled the Earth in 1831.

— It’s hard to imagine what our dinner plates might look like without the modern-day potato, but where did it come from? The tuber apparently evolved from a chance encounter involving a wild tomato millions of years ago.

— Like King Arthur, the Song of Wade was once a popular epic, but it has few surviving phrases today. A newly decoded error shows the long-lost saga wasn’t packed with supernatural creatures as previously believed.

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