The Aral Sea is a large lake located on the border between Kazakhstan and Uzbekistan. It was once one of the four largest lakes in the world, but due to the diversion of its feeder rivers for irrigation, it has been shrinking since the 1960s. As a result, the lake has lost over two-thirds of its surface area and most of its volume. The Aral Sea is now considered an environmental disaster, with its salinity levels increasing and its fish population declining.