Russia conquered the territory of present-day Uzbekistan in the late 19th century. Stiff resistance to the Red Army after the Bolshevik Revolution was eventually suppressed and a socialist republic established in 1924. During the Soviet era, intensive production of "white gold" (cotton) and grain led to overuse of agrochemicals and the depletion of water supplies, which have left the land degraded and the Aral Sea and certain rivers half dry. Independent since 1991 upon the dissolution of the USSR, the country has diversified agricultural production while developing its mineral and petroleum export capacity and increasing its manufacturing base, although cotton remains a major part of its economy. Uzbekistan’s first president, Islom KARIMOV, led Uzbekistan for 25 years until his death in September 2016. His successor, former Prime Minister Shavkat MIRZIYOYEV, has improved relations with Uzbekistan’s neighbors and introduced wide-ranging economic, judicial, and social reforms.