Caspian Sea the east often changed course to empty into the Caspian through a now-desiccated riverbed called the Uzboy River, as did the Syr Darya farther north. The Caspian also has several small islands; they are primarily located in the north and have a collective land area of roughly . Adjacent to the North Caspian is the Caspian Depression, a low-lying region below sea level. The Central Asian steppes stretch across the northeast coast, while the Caucasus mountains hug the western shore. The biomes to both the north and east are characterized by cold, continental deserts. Conversely, the climate to the southwest
Caspian expeditions of the Rus' in 913. A fleet of 500 ships reached the southern shores of the Caspian Sea through the country of the Khazars. In order to secure a peaceful passage through the land of the Khazars, the Rus' promised the Khazars half of their spoils. They sailed down the Dnieper River into the Black Sea, then into the Sea of Azov, then up the Don River past the Khazar city of Sarkel, and then by a portage reached the Volga, which led them into the Caspian Sea. The Rus' attacked in the Gorgan region around Abaskun, as well as Tabaristan, pillaging the