Vientiane (or Viengchan, Also known as Vientiane Prefecture or Vientiane Municipality) (Lao: ນະຄອນຫຼວງວຽງຈັນ, Nakhônlouang ViangChan) is a prefecture of Laos, in the northwest Laos. The national capital, Vientiane, is in the prefecture. The prefecture was created in 1989, when it was split off from Vientiane province. On a curve of the Mekong River, and bordering Thailand, the prefecture covers an area of 3,920 km2 (1,510 sq mi). Vientiane city was built in the 16th century in the reign of King Saysethathirath. The older part of the city has ancient temples, museums, monuments and parks.