the turan depression, turan lowland or turanian basin is a low-lying desert basin region stretching from southern turkmenistan through uzbekistan to kazakhstan. the lowland region lies to the east of the caspian sea and southeast of the aral sea in the vast aral–caspian depression. some of it is above sea level. it is one of the largest expanses of sand in the world, covering an area of around 3 million km2. on average, the region receives less than 15 inches (381mm) of rainfall per year. the karakum desert lies at the southern portion of the turan lowlands.