The Garabogazköl Aylagy, alternatively the Kara-Bogaz-Gol 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 . It is separated from the Caspian Sea proper, 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.