The Plain of Jars is a megalithic archaeological landscape which is now a UNESCO  World Heritage site. 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 mostly arranged in clusters of one to several hundred.

These huge jars vary in height and diameter between 1m and 3m and are all hewn from rock.

There are various legends about how these jars came to be there, but were probably a Stone Age crematorium or burial site.

Between 1964 and 1973, the Plain of Jars was heavily bombed by the U.S. Air Force who dropped more bombs on Laos, primarily the Plain of Jars, than it dropped during the whole of World War II. This included 262 million anti-personnel cluster bombs. An estimated 80 million of these did not explode and remain a deadly threat to the population. The large quantity of unexploded bombs in the area, especially cluster munitions, limits free movement. Evidence of the bombing raids can be seen in the form of broken or displaced jars and bomb craters. Sightseeing on the Plain of Jars can only be done safely on cleared and marked pathways.