Please answer the following question: The Gadar River rises in the Iranian Zagros Mountains near the point where the borders of Iran Turkey and Iraq meet. From its source the river first flows towards the southeast and then changes course due east through the Ushnu-Solduz valley. After leaving the valley the river turns north and flows into marshes bordering Lake Urmia. Given a list of categories: company, educational institution, artist, athlete, office holder, mean of transportation, building, natural place, village, animal, plant, album, film or written work, what category does the paragraph belong to?
Answer:
Natural Place