Please answer the following question: Pick one category for the following text. The options are - company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work. Pai River - The Pai River (Thai: RTGS: Maenam Pai Thai pronunciation: [mnam paj]) originates in the mountains of the Daen Lao Range Pai District Mae Hong Son Province Thailand. The river flows first in a N/S direction and then in an E/W direction down to Mueang Mae Hong Son District and across the Thai/Burmese border. The river tributes the Salween River in Kayah State Burma. It is 180 km long. The Pai river is popular for whitewater rafting and offers several options.
A:
Natural Place