Don is a river in the European part of Russia. Its source is in the Central Russian Upland, southeast of Tula city and flows northwest of Azov city into the Taganrogski bay of Azov sea. Don has a length of 1970km and the area of its basin is around 442 500 km2 . In the upper stream, Don runs in a narrow valley; the right shore is 90 meters high and the left is low and slant. The river has lots of turns and curves. The most important tributaries of the river are Nepriadva, Krasivaya Mecha, Bistraya Sosna, Voronezh. In the mid stream, near Kalach city, the valley of Don gets wider. The right shore here is also high. In the lower stream Don flows in a very wide valley (20-30 km) with wide floodplain and it is about 20m deep. Tributaries of Don are Severski Donetz, Sal and Manich. Don’s delta has area of about 340km2 . It is most abounding during the spring and least abounding during August and September. The yearly flow is 27.4km3 . In its easternmost point Don gets very close to Volga river. Both rivers are connected with the Volgo-Don channel and Zimlyanskoe reservoir. Don is navigable up to Lisiki city (1355km). Some of the biggest cities on Don are Lebedyan, Zadonsk, Pavlovsk, Rostov on Don.