Caspian Sea
The wide and endorheic Caspian Sea has a north–south orientation and its main freshwater inflow, the Volga River, enters at the shallow north end. Two deep basins occupy its central and southern areas. These facts lead to horizontal differences in temperature, salinity, and ecology. The Caspian Sea spreads out over nearly 750 miles (1,200 km) from north to south, with an average width of 200 miles (320 km). It covers a region of around 149,200 square miles (386,400 square km)—bigger than the region of Japan—and its surface is about 90 feet (27 meters) below sea level. The sea bed in the southern part reaches as low as 1,023 m (3,356 ft) below sea level, which is the second lowest natural depression on earth after Lake Baikal (−1,180 m, −3,871 ft). The ancient inhabitants of its coast perceived the Caspian Sea as an ocean, probably because of its saltiness and large size.
Cheleken Peninsula
The Cheleken Peninsula is about 40 km long and 22 km wide. It borders on the Caspian Sea in the west and with the Türkmenbaşy Gulf (former Krasnovodsk Bay) in the north. The peninsula has a continental dry climate with a precipitation of 150 mm/year. The area is desert and the central part is elevated terrain averaging 100 m elevation, with 25 m high cliffs in the central part of the western shore, while the eastern shore is low and sandy.