The Plain of Jars in the Xieng Khouang plain of Laos is one of the most enigmatic sights on Earth. The unusual scattering of thousands of megalithic jars across nearly one hundred sites deep in the mountains of northern Laos has fascinated archaeologists and scientists ever since their discovery in the 1930s.

How Were the Jars Constructed?

The unusual site known as the Plain of Jars is dated to the Iron Age (500 BC to 500 AD) and is made up of at least 3,000 giant stone jars up to three meters (9.8 feet) tall. Most are made of sandstone but there are others carved out of much harder granite and limestone. One of the big mysteries about the site is how the massive jars, some weighing up to 10 metric tons, were dragged from the quarry to be placed in groupings 10 km (6.2 miles) away.

Because most of the jars have lip rims, it is presumed that all of them were originally covered with lids. And although a few stone lids have been recorded it is more likely that the main material used for the coverings was wood or rattan .

Is this a stone lid for one of the massive jars? ( cornfield /Adobe Stock)

The jars appear to have been manufactured with a degree of knowledge of what materials and techniques were suitable. It is assumed that Plain of Jars’ people used iron chisels to manufacture them, although no conclusive evidence for this exists. Little is known of the people who carved the huge containers and the jars themselves give little clue as to their origins or purpose.

Laos, Plain of Jars with Hmong girls. (Oliver Spalt/ CC BY SA 2.5 )

According to local legend, the jars were created by a race of giants , whose king needed somewhere to store his rice wine. The wine was to be consumed at a great feast to celebrate an illustrious military victory thousands of years ago.

Legend tells of an evil king, named Chao Angka, who oppressed his people so terribly that they appealed to a good king to the north, named Khun Jeuam, to liberate them. Khun Jeuam and his army came, and after waging a huge battle on the plain, defeated Chao Angka.

One Explanation - Catching Rainwater

Some specialists claim that the effort required to have made so many jars suggests they were designed to capture rainwater during monsoon season and later boiling it for use by caravans passing through the region.

Plain of Jars, Phonsavan, Xieng Khuang province, Laos. ( flu4022 /Adobe Stock)

The Plain of Jars as an Extensive Burial Site

That is one alternative, however, most archaeologists believe that the jars were used as funerary urns . Excavation by Lao and Japanese archaeologists in the intervening years has supported this interpretation with the discovery of human remains, burial goods , and ceramics around the stone jars.

It is believed that the jars were used to place the corpses of deceased people where they were left to decompose or ‘distill’, a practice that has been common in Thailand and Laos, usually in pits. It is believed that the bodies were left in the jars for the soft tissue to decompose and the body to dry out before being cremated. Once they had been cremated, the ashes would have been returned to the urns, or perhaps buried in a sacred place, freeing the jars for re-use to decompose another body.

A group of stone jars at the Plain of Jars, Thong Hai Hin Site 1, at Thomghaihin near the town of Phonsavan in the province Xieng Khuang in Laos in Southeast Asia. ( cornfield /Adobe Stock)

Recent Findings at the Plain of Jars

In 2016, archaeologists Dougald O’Reilly and Nicholas Skopal, from the Australian National University, and colleagues announced their discovery of 15 new sites containing 137 new examples of the more than 1500-year-old massive jars.

The new sites show that the distribution of the jars is wider than previously thought. This research brings the total number of jars to over 400, which strongly suggests to the team of archaeologists that “there may be thousands more spread across the entire site”.

Recent digs have revealed 18 more examples of human remains, of which over 60% were infants or babies. Researchers have also established that almost half of the children had died when they were in early infancy or still fetuses.

A team of researchers from the University of Melbourne, who excavated a popular part of the Plain of Jars, known as ‘Site 1,’ support the idea of it having been primarily used for burial practices. Lead author Louise Shewan told IFL Science that “Site 1 contained three types of mortuary ritual practices: secondary burial of human bone, secondary burial of human remains in buried ceramic jars , and for the first time, a primary burial of two individuals”.

Speaking on the diversity of burial styles, Dougald O’Reilly said: “Our research, while in preliminary stages, has revealed a wide range of mortuary practices . Such diversity of practice in disposal of the dead is uncommon in one culture... there may be several explanations for this diversity and we hope to establish why this is the case.”

Researchers have also found beautifully-carved discs with geometrical images of concentric circles , human figures, and animals, all of which were discovered buried with their decorated sides positioned face-down. Some researchers claim they are probably burial markers .

Mystery of the Plain of Jars, Phonsavan, Laos, Southeast Asia . ( samantoniophoto /Adobe Stock)

However, most of the human deposits were made in the jars much later than they were created, with radiocarbon dating showing the jars have been around since as far back as 8,200 BC to 1,200 AD.

The Mystery of the Plain of Jars Continues

Archaeologists still don’t have all the answers but unfortunately their work is slowed by the fact that the Plain of Jars is one of the most dangerous archaeological sites in the world. Scattered over the plains are literally thousands of tons of unexploded bombs, land mines, and other unexploded military ordnance. These munitions contaminate more than 35% of the province's total land area and continue to threaten the lives of the 200,000 people who now live in Xieng Khouang.

Rusty metal bomb casings and defused unexploded ordnance found in Phonsavan, Xieng Khouang Province, Laos. ( cornfield /Adobe Stock)

Top Image: Plain of Jars, Phonsavan, Xieng Khuang province, Laos. Source: elnavegante /Adobe Stock

By Joanna Gillan