The Garabogazköl Aylagy, alternatively the Kara-Bogaz-Gol (literally "mighty strait lagoon") is a shallow inundated depression in the northwestern corner of Turkmenistan. It forms a lagoon of the Caspian Sea with a surface area of about 18,000 km2 (6,900 sq mi). It is separated from the Caspian, which lies immediately to the west, by a narrow, rocky ridge having a very narrow opening in the rock through which the Caspian waters flow, cascading down into Garabogazköl (whence the name of the bay—"Mighty Strait Lake" in the Turkmen language—comes). The water volume of the bay fluctuates seasonally with the Caspian Sea; at times it becomes a large bay of the Caspian Sea, while at other times its water level drops drastically. The city of Garabogaz (formerly Bekdaş) lies on the ridge, about 50 km north of the channel between the main Caspian basin and the Garabogazköl lagoon. The town has a population of about 10,000.