The Caspian sea, the biggest lake in the world, divides Europe from Asia, and is also the western boundary of Turkmenistan with its 1.200 km of coastline. Owing to its scale and geographical composition, once an ocean floor, the Caspian is called a mar. At the height of 27 m below sea level, the gross area of the Caspian Sea is about 371,000 m2, while the max. depth of the Caspian Sea exceeds 1,025 m. The water is saline in the Caspian Sea.
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.
This bay is in Turkmenistan’s north-west portion. The Turkmen language is translated as the “lake of black strait;” but Kara-Bogaz is a “black throat” in the other interpretion. In fact, these areas have been seen as deadly in centuries past.
The Gulf of Kara-Bogaz-Gol is currently a separate lake connected to the Caspian Sea by a narrow isthmus of less than 200 meters in diameter. It is also below the Cospian Sea, taking in thousands to 15 million tons of salt per year, millions of cubic meters of waters flow there. The Kara-Bogaz-Gol water surface varies continuously in the overall region because of the high degree of evaporation and when it is dried, clusters of mirabilite crystals (salt Glauber) grow on its shores. Therefore, it is often called a “sea of white gold” in comparison to its name. The site is known for its mirabilite production, which is commonly used in the chemical and pharmaceutical industries.