Plain of Jars is a megalith in Laos, Asia. UNESCO World Heritage List: Megalithic Jar Sites in Xiengkhuang - Plain of Jars gives its chronology as “c. 500 BCE to 500 CE.” Its listed material is Sandstone. Its height is listed as 3 m (estimated). UNESCO World Heritage List: Megalithic Jar Sites in Xiengkhuang - Plain of Jars also records: “Mortuary practice.”
Thousands of carved stone jars up to 3 m tall scattered across upland Laos.
What makes it extraordinary
Strategic Landscape Alignment and Trade Routes
Jar sites are typically situated on ridges, spurs, and elevated landscape features that offer commanding views of the surrounding lowlands. This placement may reflect displays of territorial control or social power. Geographically, the Xiangkhoang Plateau provides relatively easy passage between the north, east, south, and west. The locations of the jars are believed to be associated with long-distance overland routes connecting the Mekong basin and the Gulf of Tonkin, suggesting the sites functioned as a network of intercultural villages linked to mining and trading.
Stone Discs and Rare Anthropomorphic Carvings
Approximately 200 stone discs have been found near the jars, featuring at least one flat side. Although once thought to be lids, their failure to fit the jars suggests they served as burial markers. Many discs feature anthropomorphic and zoomorphic iconography, including 'spread-eagle' human figures and animals like tigers and monkeys. Notably, only one jar (at Site 1) has been found with a carved exterior, depicting a 'frogman' bas-relief that shares stylistic parallels with 500 BC–200 CE rock paintings in Guangxi, China.
Physical Dimensions and Geological Composition
The stone jars vary in height and diameter between 1 and 3 meters, with some individual vessels weighing up to 14 tons. They are hewn from five distinct rock types: sandstone, granite, conglomerate, limestone, and breccia. Sandstone is the most common material, particularly for the largest jars, which are typically found in mountainous areas. Granite jars are rare, found only in the Khun District, and often show significant weathering and smaller dimensions due to the difficulty of cutting the hard rock mass.
Quarrying Techniques and Logistical Coordination
The construction of the jar sites required significant social organization and advanced logistical planning. Partially hewn jars still embedded in bedrock at quarry sites near Sites 2 and 3 provide evidence of on-site extraction. While it is assumed iron chisels were used, experimental archaeology has demonstrated that lithic tools could also achieve the necessary shaping. Transporting vessels weighing up to 14 tons across rugged terrain, sometimes from quarries nearly 100 kilometers away, implies a stratified society capable of mobilizing large, specialized labor forces.
Impact of Unexploded Ordnance on Research
Archaeological study of the Plain of Jars has been severely restricted by unexploded ordnance (UXO) from the Secret War in Laos. Between 1964 and 1969, the U.S. Air Force dropped an estimated 270 million cluster bombs on the region, with approximately 80 million failing to detonate. Although organizations like the Mines Advisory Group (MAG) and UNESCO have cleared several sites for visitors, less than 10% of the megaliths have been thoroughly investigated due to the ongoing hazard, which continues to threaten local populations and damage the jars.
Chronology and Scientific Dating of the Jars
Researchers using optically stimulated luminescence have determined that some jars were put in place as early as 1240 to 660 BC. Additional dating at Site 1 using detrital zircon geochronology confirmed the stone was transported from a quarry approximately eight kilometers away. While the jars themselves date to the Iron Age or earlier, excavations at Site 1 by the Lao-Australian Plain of Jars Archaeological Project confirmed the site was also used for secondary burials much later, between the 8th and 13th centuries CE.
Megalithic Landscape of the Xiangkhoang Plateau
The Plain of Jars is a megalithic archaeological landscape located in the upland valleys and lower foothills of the central Xiangkhoang Plateau in Laos. The site consists of thousands of stone jars arranged in clusters that range from a single vessel to several hundred. While over 120 jar sites have been identified across the province, UNESCO officially recognizes more than 50. Documented sites currently include over 2,100 individual jars, with the largest known site, Site 52, containing 392 jars.
Funerary Purpose and Secondary Burial Practices
Archaeological evidence strongly associates the jars with burial practices. Excavations have uncovered human remains both inside the jars and in surrounding burial pits. In 2023, Site 75 yielded the first substantive instance of uncremated human remains found directly inside a stone jar. Analysis suggests the jars may have functioned as 'distilling vessels' for the decomposition of bodies before final cremation or secondary burial, a practice that mirrors traditional Southeast Asian royal mortuary rituals where the soul transforms from the earthly to the spiritual world.
Social Hierarchy and Regional Trade Networks
Variations in jar size and the quality of associated grave goods indicate a socially stratified Iron Age society. The discovery of non-local items, such as glass and carnelian beads, bronze objects, and iron tools, suggests the civilization was economically connected to trade routes linking China and Vietnam. The labor-intensive process of creating larger, more elaborately crafted jars likely reserved these vessels for elite members of society, such as chieftains, while commoners may have been buried in surrounding pits without cremation.
Early Research and the Site 1 Crematorium
Archaeological research began in 1935 with Madeleine Colani, who documented 21 sites and identified Site 1 (Ban Ang) as a primary location. Colani discovered a natural limestone cave at Site 1 with two man-made holes at the top, which she interpreted as chimneys for a crematorium. Her excavations inside the cave revealed burned bones and ash, leading to the theory that the jars served as funeral urns. Modern research has confirmed that Site 1 was used repeatedly over generations for secondary burial practices.