For nearly a century, thousands of massive stone urns scattered across north-central Laos have stood as one of archaeology’s most baffling enigmas. Local folklore said ancient giants had carved the hollowed-out megaliths to brew celebratory rice wine.

But scientists have long suspected a far more solemn purpose: interment of the dead. Now, a study published in Antiquity offers compelling evidence to prove the scientists right.

In winter 2022, on the windswept Xieng Khouang Plateau, in an area aptly named the Plain of Jars, the study’s authors became intrigued by a peculiar, squat structure, roughly 1.3 metres tall and more than 2 metres wide. Looking closely at the stone vessel, they decided to excavate the sediment that had accumulated within its cavity.

“The jar looked a bit like a giant stone cauldron that had collapsed in on itself,” said Nicholas Skopal, an archaeologist at James Cook University in Australia and the lead author of the paper.

What he and his team found inside shattered the wine-vat myth and redefined our understanding of early Southeast Asian history. The vessel they named Jar 1 was essentially a multigenerational crypt packed with the jumbled, disarticulated remains of at least 37 people.

“Honestly, it was one of those rare excavation moments where everyone becomes very quiet,” Skopal said. “We expected archaeology, but not such a dense, intact concentration of body parts.”

The burial site revealed an artfully arranged communal tomb that required careful planning and curation. To maximise the limited capacity of the chamber, the space had been meticulously organised.

Skulls were neatly stacked around the jar’s rim while the longer thigh bones were laid across the edges. To Skopal, the tidy, space-saving layout pointed to a tomb for an entire family, lineage or close-knit community. “Essentially, it was an ossuary,” he said.

The deceased, whose bones ranged from those
of infants to adults, were most probably placed into what the scientists call
the “death jar” long after their demise.

Researchers believe these indigenous peoples practiced secondary burial, a ritual in which bodies were first allowed to decompose elsewhere — among other things, by temporary entombment, exposure or smoke-drying — before the bare bones were gathered and interred collectively, a widespread practice throughout the period in Southeast Asia.

French archaeologist Madeleine Colani introduced the Plain of Jars to the contemporary world in the mid-1930s. Digging inside a limestone cave near one site, she found ash, charcoal, burnt teeth and bone fragments.

She deduced that the cave had functioned as a crematory and hypothesised that the jars were funerary urns designed to hold incinerated human remains. But she found very few organic materials inside the jars themselves.

Colani dated the basins to the Iron Age (500 BCE to 500 CE). But radiocarbon testing of Jar 1 showed that it had served as a shared burial centre for roughly 270 years, from the 9th to the 12th centuries, just as medieval Asia was undergoing sweeping transformations. Over the course of three field research seasons, the team led by Skopal and Souliya Bounxayhip, an archaeologist with the Lao Department of Heritage, uncovered a stash of iron tools, earthenware, stone slabs, a copper-based bell and glass beads.

Chemical analysis revealed that the exotic baubles had travelled from places as distant as Mesopotamia and South India, proving that this wide, upland plateau was far from isolated — it was a bustling hub of global commerce.

While the trailblazing Jar 1 was sculpted from coarse-grained, sedimentary rock, ancient artisans mostly relied on readily available sandstone. The geographical sprawl of the crocks is a puzzle: some stand rigidly at attention across jagged ridges, while others rest flush against sloping mountainsides.

“Larger jars may have had greater social or ritual importance,” Skopal said, “but we cannot yet say that size equals status.”

Whether this scattershot architectural approach indicated shifting cultural rituals, evolving community traditions or the diverse tastes of distinct social classes remains an open question, though it underscores that this was one of antiquity’s more resilient and resourceful societies.

Nigel Chang, an archaeologist at James Cook University, who specialises in Southeast Asian prehistory, said the unearthing of Jar 1 offers “the most concrete, irrefutable evidence yet of how the vessels actually functioned in ancient mortuary practices”. He describes the finding as “incredibly consequential”.

While the discovery helps clear up one mystery, it fuels a multitude of new ones. Scholars are left with questions regarding who the plateau people were, how they lived and what caused their demise.