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. Silala River -  The Silala River or Silala Spring is a river which rises in Bolivia and flows into Chile. A canal constructed under a Bolivian concession carries the water into Chile.The division of the flow from this river has been a matter of controversy between the two nations Chile claiming that the present route makes it an international river.
A:
Natural Place