The Aral Sea (Kazakh: Арал Теңізі Aral Teñizi; Uzbek: Orol Dengizi; Russian: Аральскοе Мοре Aral'skoye More; Tajik:Баҳри Арал Bahri Aral; Persian: دریاچه خوارزم Daryâche-ye Khârazm) was a lake that lay between Kazakhstan (Aktobe and Kyzylorda provinces) in the north and Karakalpakstan, an autonomous region of Uzbekistan, in the south. The name roughly translates as "Sea of Islands", referring to more than 1,534 islands that once dotted its waters.

Formerly one of the four largest lakes in the world with an area of 68,000 square kilometres (26,300 sq mi), the Aral Sea has been steadily shrinking since the 1960s after the rivers that fed it were diverted by Soviet Union irrigation projects. By 2007 it had declined to 10% of its original size, splitting into four lakes – the North Aral Sea and the eastern and western basins of the once far larger South Aral Sea and one smaller lake between North and South Aral Sea. By 2009, the south-eastern lake had disappeared and the south-western lake retreated to a thin strip at the extreme west of the former southern sea. The maximum depth of the North Aral Sea is 42 m (138 ft) (as of 2008).