evidence: Lao People's Democratic Republic or Laos (ປະເທດລາວ), is a country in Southeast Asia. The capital of Laos is Vientiane. [...] Geography [change | change source]Laos is the only landlocked country in Southeast Asia. The landscape is mostly rugged mountains. The highest point is Phou Bia at 2,818 metres (9,245 feet). The Mekong River forms the border with Thailand. The mountains of the Annamite Range form the eastern border with Vietnam. The climate is tropical. The rainy season is from May to November. The dry season is from December to April. Laos has three seasons (rainy, cold and hot). The capital and largest city is Vientiane.