The town of Phonsavan is in the Province of Xieng Khouang, one of the poorest in Lao. It is the gateway to the mysterious Plain of Jars which lies southeast of the town. The Plain of Jars is an impressive archaeological site where hundreds of large stone jars are scattered all over the plateau. It is one of Southeast Asia's most mysterious sights, and historians remain uncertain of where the jars came from, how they got to the plain or what they were for. So far the most popular theory is that they were enormous burial urns for an ancient civilisation.The landscape in this area is quite unique in Laos partly because it is on an elevated plain, meaning the weather is much cooler than the rest of Laos and also because during the Vietnam War the Americans bombed communist Pathet Lao positions up here creating huge craters and making it the most heavily bombed place on earth.