Akchakaia

an undrained sink in the northwestern section of Karakum, in the Turkmen SSR. Its length is about 50 km, its width about 6 km, and its relative depth 200 m. The bottom of the hollow lies 81 m below sea level (second in depth to the Karagie Sink in the USSR). Curved in the shape of a horseshoe, it has high, steep sides. It was first studied in 1935 by the Soviet geographer E. M. Murzaev.