laotian karst limestone landscape, en route to vang vieng from phonsavan

2000 2019 2800m archeological asia asian characterized collective formation formations funerary geological heritage high inscribed jars karst landscape laos laotian limestone located location mountains name north northern phonsavan plain plateau province range remains route rugged several site sites southeast topography unesco vang vieng vientiane was which world xiangkhoang xiangkhouang