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

The Plain of Jars is an area of about 2,000 square miles in Northern Laos that contains clusters of open-air stone vessels of various sizes and shapes. The vessels are megalithic jars that measure as tall as 10 feet and can weigh up to 30 tons. Altogether, there are more than two thousand jars and hundreds of strange stone discs that date back to the Late Iron Age, around 500 BCE. Archaeological discoveries since 1931 have revealed many mysteries about the dotted plains – questions that have yet to be answered.

Plain of Jars Laos

The Plain of Jars spans two provinces in Northern Laos and contains about 85 archaeological sites. Flickr: Damien Farrell.

The first archaeologist to explore 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 the 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).

Lia Genovese of Thammasat University in Thailand is one of the leading archaeologists currently studying the jars. She has documented many new findings across the Laotian jar sites and has taken a close look at the odd differences between the jars.

Sites in the Plain of Jars

The Plain of Jars spans the Xieng Khouang and Luang Prabang provinces. 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 for other reasons.

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; 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 rare 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 jars are made of natural rock: limestone, granite, breccia, composite and sandstone. Most of the stones came from local quarries in the surrounding areas. However, some derived from neighboring regions a little farther away.

Many 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. Typically, they are “barrel-shaped,” but there are versions that are more round, squarish or oblong. A few have a hole on the side, possibly for the placement of votives or other ritual items. Less common are a few jars that have animal or human figures as decorations.

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.

In 2016, an Australian team led by Dougald O’Reilly announced their discovery of one entire human skeleton in a ground-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.

Stone Discs

Archaeologists have documented about 200 stone discs around the Plain of Jars, however, their purpose is yet another one of the many historic mysteries of the area. 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. 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
In the photo 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.


Why This Location?

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.

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. Additionally, the elevation may have made for auspicious burials.

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

Purposes of the Jars

There is not yet enough evidence to reveal how this ancient group of people specifically 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. Perhaps they placed the body in the jars for some time, then later cremated the body and buried the remains in clay pots in the ground.

Locals have their own legends about the history of the Plain of Jars. One story involves giants who once inhabited the land and used the massive jars for drinking. Another legend says the jars were vessels to ferment a large amount of rice wine.

Who Created the Funerary Sites?

There is much uncertainty about the people who lived in these Laotian provinces during the Iron Age. Human existence around the area of the jars dates back much further than once thought. A skull found 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. Some experts assert that the Tai people replaced earlier Austroasiatic people who probably created the jars during the Iron Age. However, more research on the settlements around the area is essential to providing more specifics.

Importance of Conservation

There is a large amount of unexploded ordnance (UXO) that blanket the area and hinder excavations. The 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, of which about 30% are unexploded.

Meanwhile, jars, lids, and discs that survived the bombings are continually facing damage. 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.

Mysteries Endure in the Plain of Jars

The Plain of Jars invokes many questions but can provide few answers at this time. The civilization that made the jars has long disappeared. However, 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. Why are there so many jar and lid variations from site to site? What were the open-air jars used for versus the clay pots buried in the grounds? What was the ethnicity of the people that made them and what happened to them? 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.

Drone Flights Over the Plain of Jars

Take an aerial tour of the mysterious jar plains

You May Also Like to Read:
Angkor Wat: The Enduring Pride of the Khmer Empire

Genovese, Lia. 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.
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.

Historic Mysteries