Guangxi is an autonomous region in southern China, bordering Vietnam. The area is known for its rivers, caves and towering karst formations. Boat cruises on the Li River connect Guilin and Yangshuo, cities punctuated by toothlike karst peaks. Guilin is the site of Ludi Yan (Reed Flute Cave), a limestone cavern noted for its stalactites and stalagmites. Area: 236,700 km² Population: 48.38 million (2016)