The Plain of Jars: Mysteries of Laos’ Iron Age Megaliths

In Northern Laos, there is an area of about 2000 square miles called the Plain of Jars. Clustered across the landscape are open-air stone vessels of various sizes and shapes. These megalithic jars measure as tall as 10 feet and can weigh up to 30 tons or 60,000 pounds. Altogether, there are more than 2000 jars and hundreds of strange stone discs that date back to the Late Iron Age, around 500 BCE.

The Plain of Jars in Northern Laos

The Plain of Jars in Laos. Credit: Carrie Kellenberger, Flickr.

The Plain of Jars may have been a ritually sacred expanse of land with undulating hills, mountain slopes, rivers, spring water stations, abundant sources of stone and, above all, a place associated with ancient burials

Lia Genovese

The first archaeologist to survey the Plain of Jars was Madeleine Colani with the École française d’Extrême-Orient between 1931-1933. Her excavations remain the most extensive work in this area. Colani surveyed 12 sites in the jar fields of Laos and published her findings in her paper, Mégalithes du Haut-Laos.

Lia Genovese with stone jar in the Plain of Jars

Genovese standing next to a massive sandstone jar. Photo: Courtesy Lia Genovese (2017).

Current fieldwork in North Laos by the prominent archaeologist, Lia Genovese, of Thammasat University in Thailand, greatly influences this article. She has documented many new findings across the Laotian jar sites and has made incredible comparative analyses of the characteristic differences of the jars between sites in Laos and other nearby countries.

Sites in the Plain of Jars

The Plain of Jars extends into two provinces of Northern Laos, Xieng Khouang and Luang Prabang. There are approximately 85 designated archaeological sites, and each site contains anywhere between 1 and more than 400 jars. The most visited and accessible sites are those first investigated by Colani, Sites 1, 2, and 3, near the Xieng Khouang provincial capital, Phonsavan.

In 2014 only 8 sites were open to visitors. Many sites are off-limits due to unexploded bombs (UXO) from the Vietnam War. Some sites are further away from the tourist accommodations, require a long hike, or are inaccessible.

Archaeological Discoveries

Strange Jar Shapes

Interestingly, there are many variations in the mysterious jars and discs (discussed in the next section) from one district to another and from province to province within Laos. One thing the jars all have in common is that they are all megaliths. This means they consist of one large stone block carved into various sizes and shapes. Most have an opening on the top and a flat base, although there are examples of one opening on each end.

plain of jars

Longer cigar-shaped jar with inner rim, Site 2, 2008. Credit: Flickr, amanderson2 CC.

The mysterious culture that made the jars used a variety of natural rock: limestone, granite, breccia, composite and sandstone. Most of the stones came from local quarries in the surrounding areas. However, some came from neighboring regions a little farther away.

Most of the jars have flat top rims, but a version with inner rims exists at a few sites. Colani thought this was possibly for the placement of a stone lid. Some jars have longer necks, but this is not the norm. Many of the jars are “barrel-shaped,” while some are more round, squarish or oblong. The sizes range from around 3-10 feet tall (or long). A few have a hole on the side, possibly for placement of votives or other ritual items. Animal or human figures decorate the side of a few jars.

Human Remains

A 2009 UNESCO training manual on the Laos jar fields attests to human remains inside the jars. However, Lia Genovese asserts that “human remains have not been found inside the stone jars, with the exception of ash in a small number of jars at two sites only, although the cremations could have been carried out in recent decades.” Terracotta pots buried in the ground around and under the jars in burial pits did contain human teeth and bones. Colani documented that some sites contained buried cremated human remains, while other sites only contained buried uncremated remains. Archaeologists have not found any complete human bodies in any of the vessels.

In 2016, an Australian team led by Dougald O’Reilly announced their discovery of one entire human skeleton in a buried grave at the Plain of Jars, Site 1. The team found the body using ground penetrating radar (GPR). More research may determine how old the body is, and more excavations using GPR may help to find additional skeletons.

“Male” and “Female” Jars

The reasons for the different shapes and sizes is a mystery. However, one plausible theory put forth by Colani regarding at least some of the variation of the monoliths of Northern Laos suggests “male” and “female” gender assignments for the purpose of fertility rites. Genovese relates a story in which some of the locals told her about moving two different jars. They referred to the jars as “male” and “female.”  The male jar had a neck on it, while the female jar just had a flat rim on top. It may be that, like so many ancient cultures, the Iron Age people that made the jars associated their gods with fertility and represented this belief in some of their jar megaliths.

Stone Discs

Archaeologists have documented about 200 stone discs around the Plain of Jars, however, their purpose is yet another mystery. The discs range in size but are generally no more than 3 feet wide. Additional variations exist in their design. Many of them are pancake-shaped, but others are more like button mushrooms. Although most of them are plain, some have a pommel or finial on top, similar to what someone would grab to lift the lid off a small jar. A small number of discs exhibit a relief carving of a human, animal, or concentric circles.

Genovese standing by disc in the plain of jars
Above, Lia Genovese is standing next to a rare sandstone disc decorated with a feline figure in the remote district of Phou Khoun in Luang Prabang Province. The dome in this image has a circumference of 410 cm and a thickness of 50 cm. (Photo courtesy Lia Genovese 2017).

Examples of stone lids in the Plain of Jars

(L) Stone disc with pommel. (R) Stone disc with human figure. Flickr: John Pavelka, Amandersson 2.

Colani argued that the larger discs were not used as lids to the jars since many of them were not the same size as the jar openings. But she does mention that rounder, smaller stones buried in the ground are lids to the clay pots. To add to the mystery of the discs, it is odd that the number of discs is only one tenth the number of jars in the Plains.

zoomorphic domes at plain of jars

Luang Prabang Province. Sandstone dome decorated with zoomorphic figure. Source: M. Colani. 1935. Mégalithes du Haut-Laos (Hua Pan, Tran Ninh), École Française d’Extrême-Orient (EFEO), XXV, Paris, vol. 1, pl. 53, 59.

UNESCO indicates that the plain flatter discs are burial markers placed on burial pits. The ones with filial-type pommels on top are lids. None of the jars at any time were initially seen with covers. Therefore, there is still much uncertainty about lids and discs.

The Cave At Site 1 – Ban Ang

Madeleine Colani excavated a cave that she discovered at Site 1 (called Ban Ang). The roof of the cave had two holes that she believed were man-made. She also found cremated human bone around the cave. Also, humans had made the opening of the cave wider than its original opening. These clues led her to believe that ancient people had used the cave as a crematorium. The holes may have been chimneys.

Within the last ten years, archaeologists have excavated some other caves around the cemetery fields, such as the Tham An Mah cave in the Luang Prabang province. Findings include ashy deposits, buried pots with human remains, and discs or boulders directly overlaying the burial pots. They discovered both cremated and uncremated remains in the cave as well. These Iron Age discoveries suggest a direct connection to the culture of the jars and the pots found buried in the fields.


The Mysterious Plain

Locals have their own legends about the Plain of Jars history. One story involves giants who once inhabited the land and used the giant jars to drink from. Another legend says the jars were vessels to ferment rice wine. The villagers then drank the wine during a seven-month long celebration after a victory over a despotic ruler sometime around the 7th century CE.

Another more plausible theory suggests that these areas were very ancient burial grounds. This may have been the case well before the advent of the open-air jars. In addition to the full human skeleton buried in Site 1, there was a 3000-year-old skull found at the same site. Although scientists did not find any grave goods with it, the presence of the ancient bone may possibly tell us that people were using the fields for burials even at that time.

It appears that the ancient creators of the jars carefully chose this location as a graveyard. The reasons are purely speculation. However, they may have found it to be a particularly auspicious area for spiritual reasons. The elevation of up to roughly 4000 feet may hold clues. There is evidence that tells us some Asian cultures believed higher elevations are closer to heaven.

The reason the jars are scattered the way they are around the land in clusters is a mystery. But the placement of the jars near burial pits and pots that contain human remains and goods is what leads scholars to believe that the jars had something to do with the burial process. In some cases, the jar sits directly above a buried pot that contains remains.

There may also have been other benefits to this location. Scholars have suggested that the area was an intercultural crossroad or a corridor for trade. Thus, the Laotian burial fields may have served a variety of communities.

Purposes of the Jars

There is not enough evidence to reveal how this ancient group of people used the jars. Many scholars guess that their purpose was to “distill” human bodies. Some Asian cultures believed the spirit does not leave the body immediately but in a slow process. So they placed the body in the jars for some time. Then later, they cremated the body and buried the remains in clay pots in the ground.

Who Created the Funerary Sites?

Human existence around the Plain of Jars dates back much further than once thought. A skull discovered in the Tam Pa Ling cave of Northern Laos has proven to be about 63,000 years old. However, this does not prove that a burial culture existed there, as the skull washed into the cave; someone did not bury it there. Also, scientists did not find any burial goods of that age.

The people who inhabit the region around the jar fields today have only been there about a thousand years. Their descendants, the Tai group, began migrating into the area from Southern China around 500 CE. They replaced the earlier Austroasiatic people who probably created the jars during the Iron Age. However, more research on the settlements in the area is essential to providing more specifics.

Madeleine Colani believed the geographic region of the jars may have served as a hub along a trade route between India and Vietnam. Indeed there are some similarities between Indian Assam jars and the jars in Northern Laos. There are also similarities in the types of burial artifacts between Vietnam and Laos, such as beads.

Importance of Conservation

Many mysteries remain in the burial fields of Laos. This is in part a result of the amount of unexploded ordnance (UXO) that blanket the area. Excavations are hindered under these conditions. The Plain of Jars bombing was an effort by the U.S. to thwart the movement along the Ho Chi Minh Trail during the Vietnam War. The National Regulatory Agency indicates that between 1964 and 1973 the U.S. dropped more than 200 million tons of ordnance on Laos. This included 270 million cluster bombs. They estimate that 30% of the ordnance did not explode. Today, the entire country is contaminated with unexploded bombs. The agency reports that UXOs maim and injure 300 people each year in Laos.

Many jar sites still contain UXOs and are inaccessible to researchers. Hence, Madeleine Colani’s excavations and reports from the 1930s continue to be the most comprehensive to date. Although decontamination efforts are underway, the process is slow and costly.

Meanwhile, jars, lids, and discs that survived the bombings are continually facing damage. There are many reasons for this. The elements, farming, and vandalism by locals and tourists take their toll. Additionally, development and people who use the jars for various domestic purposes harm the sites. Sadly, many people who do not understand the historical and cultural significance throw garbage into the jars or walk and play on them.

Mysteries in the Plains Endure

The Plain of Jars invokes many questions but can provide few answers at this time. The civilization that made the jars has long disappeared. But they demonstrated a highly developed sense of spiritual beliefs. They thought out and planned very carefully their funerary processes and where they would take place. And they skillfully designed and carved jars, lids, discs and clay pots for funerary rites. More research is essential to unlocking the enigmas that still perplex scholars. Until then, this unique and rich Laotian archaeological site will remain a partially written chapter of history just waiting to be finished.

Drone Flights Over the Plain of Jars

Take an aerial tour of the mysterious jar plains

Genovese, Lia(1). “The Plain of Jars: Mysterious and Imperilled.” Global Heritage Network. February 2012. Accessed March 28, 2017.
Genovese, Lia(2). “The Plain of Jars in the Context of South and Southeast Asian Archaeology.” Academia. 2016. Accessed March 28, 2017.
Roberts, Nicholas. “The Cultural and Natural Heritage of Caves in the Lao PDR: Prospects and Challenges Related to Their Use, Management and Conservation.” The Journal for Lao Studies, 2015, 120. Accessed March 28, 2017.
Lewis, White, and Bouasisengpaseuth. “A buried jar site and its destruction: Tham An Mah cave, Luang Prabang province, Lao PDR.” Research Gate. January 2015. Accessed March 28, 2017.
Kincaid, Andrew. Oddly Historical. January 13, 2017. Accessed March 28, 2017.
Featured social media image credit: Carrie Kellenberger.

Kimberly Lin

Kimberly's number one passion is bringing history to the world, and she has written for various websites since 2011. She spent several years living in Italy and her travels in Europe and Asia have given her a keen interest in archaeology, world history, culture, and really great food. Her degrees are in International Business and Finance from the University of Hawaii.