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. Gryaznukha River - Gryaznukha (Russian: ) is a river in Perm Krai Russia a right tributary of Kungur River which in turn is a tributary of Iren River. The length of the river is 19 km.
A:
Natural Place