The Aral Sea is--or was--a large body of water in Central Asia. It is divided between the nations of Kazakhstan and Uzbekistan. While the Soviet Union existed, the Aral Sea was entirely within its borders.
Two rivers, the Amu Darya and Syr Darya, were the primary sources of water for the Aral Sea. In the 1960s, the Soviets diverted the two rivers in an attempt to irrigate the nearby desert lands and make them arable.
The result was an ecological disaster. The Aral Sea gradually shrunk into three small basins connected by narrow channels. According to NASA satellite imagery, one of those basins has now completely evaporated, leaving the Aral Sea with only 10% of its original capacity. In the photo above, you can see an outline showing the approximate shape of the lake in 1960. The fields of blue are all that is left.
(Image of Russian Aral Sea warships from The Russians in Central Asia by E. Stanford, 1865)
It was not always so. Prior to Soviet activity, the Aral Sea was a thriving lake that was a center for fishing and commerce. It was of such great importance that the Imperial Russian Navy maintained a fleet of warships there starting in 1852.
These warships were built in Sweden or elsewhere in Russia, then transported down rivers to the Aral Sea. They were based at the town of Raim, which is now a Kazakh town on a small lake about 30 miles away from the remains of the Aral Sea.
By 1880, this flotilla consisted of 6 armed vessels and several unarmed vessels. They provided mercantile security, conducted hydrographic surveys, and supported troops who campaigned in the area in 1868 and 1873. In 1883, the flotilla was disbanded, with some portions transferred to the Russian naval presence on the Amu Darya, a river that flows into the Aral from Afghanistan.
During the Russian Civil War (1917-1923), the Soviets briefly maintained a fleet of warships to combat Tsarist and British troops in the area. But with the Red victory, the need for a fleet evaporated. And, later, so did the sea on which it had sailed.