The Plain of Jars (Lao: ທົ່ງໄຫຫີນ Thong Hai Hin, ) is a megalithic archaeological landscape in Laos. It consists of thousands of stone jars scattered around the upland valleys and the lower foothills of the central plain of the Xiangkhoang Plateau. The jars are arranged in clusters ranging in number from one to several hundred.

The Xiangkhoang Plateau is at the northern end of the Annamese Cordillera, the principal mountain range of Indochina. French researcher Madeleine Colani concluded in 1930 that the jars were associated with burial practices. 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 jars. Researchers (using optically stimulated luminescence) determined that the jars were put in place as early as 1240 to 660 BC. The jars at Site 1 (using detrital zircon geochronology) were determined to have been transported to their current location from a presumed quarry eight kilometers away. Today, UNESCO officially recognizes over 50 sites, but there are additional documented sites not officially recognized. Each site has between one and 400 stone jars. Documented sites now include over 2,100 jars. The jars vary in height and diameter between 1 m and 3 m and are all hewn from rock. Their shape is cylindrical, with the bottom always wider than the top.

Stone discs were also found. The discs differ from the lids, as they have at least one flat side. Previous theories that the discs could have been lids were disproved due to that none of the discs were found on top of a jar and none would fit on the tops of the jars. Fewer discs have been found than jars, totaling 200 discs. It is possible that the discs may have been used as burial markers, as the discs were found nearby jars or could have been placed on the ground to mark a burial pit. These later excavations revealed that multiple individuals were interred in shared mortuary contexts.

No further archaeological research was conducted until November 1994, when Professor Eiji Nitta of Kagoshima University and Lao archaeologist Thongsa Sayavongkhamdy surveyed and mapped Site 1. Nitta claimed that the surrounding burial pits were contemporaneous to the jars, as they were cut into the surface on which the jars had been placed. Nitta believed the jars were symbolic monuments to mark the surrounding burials. He dated the Plain of Jars to the late second or early first millennium BC based on the burial urn and associated grave goods. Sayavongkhamdy undertook surveys and excavations between 1994 and 1996, supported by the Australian National University. Sayavongkhamdy and Peter Bellwood interpreted the stone jars as a central person's primary or secondary burial, surrounded by secondary burials of family members. Archaeological data collected during bomb clearance operations supervised by UNESCO archaeologist Julie Van Den Bergh in 2004–2005 and again in 2007 provided similar archaeological results. Like Nitta, Van Den Bergh concluded that the jars and surrounding burials were contemporaneous.

<!-- Deleted image removed: thumb|Megalithic jars at Site 1 -->

Archaeological research conducted by Dougald O'Reilly, et al. in 2018 that covered 59 sites under the Safeguarding the Plain of Jars Project, or the SPJP's, report and dozens of undocumented and possible sites, revealed that jar sites were typically built in mountainous areas and most don't have many jars, with 16 sites having between 20-60 jars and only three sites with over 200 jars.

Jar geology

The jars lie in clusters on the lower foothills and ridges of the hills surrounding the central plateau and upland valleys. Several quarry sites have been recorded, usually close to the jar sites. Five rock types have been identified: sandstone, granite, conglomerate, limestone and breccia. Quarry sites, such as those near Jar Sites 2 and 3, contain partially hewn jars still embedded in the bedrock, providing clear evidence of on-site extraction and initial shaping. Regional differences in jar shape have been noted. While the differences in most cases can be attributed to choice and manipulation of rock source, some differences in form (such as variations in the placement of jar apertures) appear to be unique to specific sites.

The majority of the jars are sandstone. The largest jars are made of sandstone and they are not found in plains or lowland areas. These large sandstone jars may only be found in more mountainous areas due to the more intensive techniques in quarrying and moving that were required for large jars, as opposed to small jars. Multiple indicators point to a complex society with distinct social classes:

Differential burial practices

  • In contemporary funerary practices followed by Thai, Cambodian, and Lao royalty, the corpse of the deceased is placed into an urn during the early stages of the funeral rites, at which time the soul of deceased is believed to be undergoing gradual transformation from the earthly to the spiritual world. The ritual decomposition is later followed by cremation and secondary burial.
  • The much larger jars were likely used as crematoriums because of the presence of burnt human remains and charcoal. This could be linked to ancient Laotian and Cambodian traditions where the bodies of elite members of society were placed in large urns to aid the soul's journey through the afterlife.

Variation in jar size and quality

The jars themselves demonstrate hierarchical distinctions:

  • Jars range from 1 to 3 meters in height, with some weighing up to 14 tons. Excavations have uncovered a wide range of burial goods; including glass and carnelian beads, iron and bronze tools and ornaments, ceramic vessels, spindle whorls, and ground stone artifacts, demonstrating both social complexity and access to imported materials. Additional finds such as ceramic ear-discs, weights, charcoal, and burnt teeth and bone fragments further highlight the diversity of mortuary practices and the specialized craft production present within the community.

Labor organization

The construction of the jar sites required significant social organization, as the stone used for the jars was quarried and transported over long distances. Jars at Site 1, for example, were shown through detrital zircon geochronology to have been moved from a quarry located about eight kilometers away, while another quarry nearly 100 kilometers distant appears to have supplied stone for other jars. Transporting stones that could weigh up to 14 tons across rugged terrain would have demanded coordinated labor forces and advanced logistical planning. The technological skill needed to carve and shape these massive vessels further suggests the presence of specialized craftspeople. These collective efforts imply a socially stratified community capable of mobilizing large groups for communal projects. Some scholars also propose that the movement to and from these sites may have been connected to ritual activities, such as ancestor worship or pilgrimage. An estimated 270 million cluster bombs were dropped or dumped on the Plain of Jars, around 80 million of which failed to detonate. This unexploded ordnance (UXO) threatens local populations, damaged jars, and restricted archaeological research for decades.

See also

  • Campaign Z
  • Bomb Harvest
  • List of megalithic sites
  • Sa Huỳnh culture
  • Giant jars of Assam

References

Sources

  • Baldock, J. and J. Van Den Bergh. 2009. "Geological Mysteries at the Plain of Jars Begin to Unravel." *Geology Today*. August 2009
  • BestPrice Travel. (n.d.). "The Plain of Jars Laos: Travel Information 2025".
  • Box, P. 2000. *Overview Mapping Using GIS, UNESCO Plain of Jars Cultural Heritage Documentation Project*, Richard A. Engelhardt, ed., UNESCO Regional Advisor for Culture in Asia and the Pacific, Bangkok.
  • Box, P. 2001. *Mapping Megaliths and Unexploded Ordnance, UNESCO Plain of Jars Cultural Heritage Documentation Project*, Richard A. Engelhardt, ed., UNESCO Regional Advisor for Culture in Asia and the Pacific, Bangkok.
  • Box, P. 2003. "Safeguarding the Plain of Jars: Megaliths and Unexploded Ordnance in the Lao People's Democratic Republic." *ESRI, Journal of GIS in Archaeology*, Volume 1-April 2003.
  • Bounmy, Thepsimuong. 2004. *The Plain of Jars. A Guide Book*. Vientiane.
  • Branfman, F. (compiled by). 1972. *Voices from the Plain of Jars - Life under an Air War*. Harper & Row.
  • Colani, Madeleine. 1935. *Megaliths du Haut Laos*. Publication de l'École française d'Extrême-Orient XXV-XXVI, Paris.
  • Coates, Karen J. 2005. "'Plain of Jars'." *Archaeology*, July/August 2005.
  • CSMonitor.com. 2016, April 5. "Researchers Begin to Crack the Mystery of Laos's 'Plain of Jars'".
  • Explorersweb. (n.d.). "Exploration Mysteries: Plain of Jars".
  • Giteau, M. 2001. *Art et Archeologie du Laos*. Editions A et J Picard, Paris, pp.&nbsp;37–57.
  • History Rise. (n.d.). "Laos' Ancient Plain Of Jars: History And Mystery Unveiled".
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  • Higham, C. 1989. *The Archaeology of Mainland Southeast Asia, From 10,000 B.C. to the Fall of Angkor.* Cambridge World Archaeology, Cambridge University Press, Cambridge. pp.&nbsp;228–230.
  • Nitta, E. 1996. "Comparative Study on the Jar Burial Traditions in Vietnam, Thailand and Laos." *Historical Science Reports*, Kagoshima University 43: 1–19.
  • Reeves Roam. (n.d.). "Visiting the Plain of Jars in Laos: A Complete First-Hand Guide".
  • Rogers, P., R. Engelhardt, P. Box, J. Van Den Bergh, Samlane Luangaphay, and Chantone Chantavong. 2003. "The UNESCO Project: Safeguarding the Plain of Jars." In A. Karlström and A. Källén (eds.), *Fishbones and Glittering Emblems: Southeast Asian Archaeology 2002*. Stockholm: Museum of Far Eastern Antiquities.
  • Rogers, P. and J. Van Den Bergh. 2008. "Legacy of a Secret War: Archaeological Research and Bomb Clearance in the Plain of Jars, Lao PDR." In E. Bacus, I. Glover, and P. Sharrock (eds.), *Interpreting Southeast Asia's Past. Monument, Image and Text. Selected Papers from 10th Conference of EASAA*, Vol. 2: 400–408.
  • Sayavongkhamdy, Thongsa and Peter Bellwood. 2001. "Recent Archaeological Research in Laos." *Bulletin of the Indo-Pacific Prehistory Association* 19: 101–110.
  • Shewan, L., O'Reilly, D., Armstrong, R., Toms, P., Webb, J., Beavan, N., Luangkhoth, T., Wood, J., Halcrow, S., Domett, K., Van Den Bergh, J., & Chang, N. 2021. "Dating the Megalithic Culture of Laos: Radiocarbon, Optically Stimulated Luminescence and U/Pb Zircon Results". *PLOS ONE* 16(3): e0247167.
  • Skopal, N., Bounxaythip, S., Shewan, L., O'Reilly, D., Luangkhoth, T., & Van Den Bergh, J. 2020. "Jars of the Jungle: A Report on Newly Discovered and Documented Megalithic Jar Sites in Lao People's Democratic Republic". *Asian Archaeology* 3: 9–19.
  • Stone, R. 2007. "Archaeology: Saving a Lost Culture's Megalithic Jars, Xieng Khouang, Laos." *Science* 315(5814): 934–935.
  • Trip Jive. 2024, November 20. "Safeguarding Laos' Heritage: Plain of Jars Preservation".
  • UNESCO World Heritage Centre. (n.d.). "Megalithic Jar Sites in Xiengkhuang – Plain of Jars"
  • Van Den Bergh, Julie. 2007. "Safeguarding the Plain of Jars, an Overview." In Y. Goudineau and M. Lorrilard (eds.), *Etudes thématiques 18. New Research on Laos – Recherches nouvelles sur le Laos*.

Further reading

  • UNESCO website for the Plain of Jars and Safeguarding the Plain of Jars Project