Caspian Sea and a Pleistocene stage, that includes glaciation cycles and the creation of the present Volga River. During the first stage, the Tethys Sea had evolved into the Sarmatian Lake, that was created from the modern Black Sea and south Caspian, when the collision of the Arabian peninsula with Western Asia pushed up the Kopet Dag and Caucasus Mountains, setting definitive south and west boundaries to the Caspian basin. This orogeneic movement was continuous throughout the years, while Caspian was regularly disconnecting from the Black Sea. In the late Pontian, a mountain arch rose across the south basin and divided it
Caspian Sea the Volga, is connected by important shipping canals with the Don River (and thus the Black Sea) and with the Baltic Sea, with branch canals to Northern Dvina and to the White Sea. Another Caspian tributary, the Kuma River, is connected by an irrigation canal with the Don basin as well. Several scheduled ferry services (including train ferries) operate on the Caspian Sea, including: The ferries are mostly used for cargo; only the Baku–Aktau and Baku–Türkmenbaşy routes accept passengers. As an endorheic basin, the Caspian Sea basin has no natural connection with the ocean. Since the medieval period, traders reached