Still unsure of their true significance, historians and lay people alike continue to be intrigued by the huge stones of the Plain of Jars in northern Laos, some of which weigh about six tons. Some stand tall as a man and tilted by time, others are eroded into the ground; many have moldered for millennia, perhaps the remnants of a trade route or the markers of burial pits. While the Plain of Jars' ancient origins remain cryptic, in the last century they have gained a different unfortunate notoriety. Between 1964 and 1973, American planes carpet bombed Xieng Khuang province, where the Plain of Jars is located, due to its close proximity to the North Vietnamese border. In just under a decade, Laos achieved the dubious distinction of being the most bombed country in the world. This sorrowful chapter in Laotian history is commemorated by the nearby Vietnamese and Lao war memorials.