The Caspian Sea, the world’s largest lake, separates Europe and Asia, and is, at the same time, the Turkmen western border with a coastline of 1,200 km. The Caspian is called a sea due to its size and geologic structure, which once was an ocean bottom. The total area of the Caspian, located at the height of 27 m below sea level, is about 371,000 km2, while its maximum depth reaches 1,025 m, which also makes it one of the deepest lakes in the world. The Caspian water is salty.
The Turkmen part of the Caspian Sea shore is predominantly indented and composed of limestone. The only major city there, is Turkmenbashi (former Krasnovodsk). There are also several bays, the largest of which is the Kara-Bogaz-Gol, connected with the Caspian Sea by a narrow isthmus.