The UNESCO World Heritage listed Plain of Jars is an area of current-day Laos which features more than 2,000 large stone jars (weighing up to 20 tonnes) dating from around 500 BCE to 500 CE.

Northern Laos is home to one of Southeast Asia’s most enigmatic archaeological cultures. The megalithic jar sites of Laos comprise one to three-metre-tall carved stone jars dotted across the landscape, appearing alone or in groups of up to several hundred. The majority of these sites are found in Xieng Khouang Province, and while collectively termed the ‘Plain of Jars’, the sites are mostly located on mountain ridges, saddles or hill slopes surrounding the central plain and upland valleys.

See : PLoS ONE, March, 2021

In the 1930s, it was concluded that the jars were associated in some way with burial practices. Subsequent research projects have shown that there definitely are traces of human remains in and around some of the jars.

Nevertheless, exactly how and why the jars were used currently a mystery. In addition, it's unknown how the extremely heavy jars were constructed and transported from quarries.