Rostov on the Don is the capital of Rostov region of Russian Federation and the administrative center of the North Caucasus district. It is located in South Eastern part of the central Russia, on the Don River near the Sea of Azov. With more than 1 million residents, Rostov is a major port, rail hub and an important industrial, cultural and scientific center. Located on the crossroad of the North Caucasus, Central Russia and the Ukraine, it is often called "The Gates of the Caucasus".